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Change Order Process: Six Details Solo Contractors Need Before Work

October 15, 2026
Change Order Process: Six Details Solo Contractors Need Before Work

A change order is a written, signed amendment to your contract that updates the scope, price, or schedule once work has already started. The moment a client asks for extra work or you hit a surprise behind the wall, stop and get that change documented and approved before you touch it. Industry guidance from the Volpe Center and the 100R-19 standard both treat this step as the backbone of a fair, provable change process.

TL;DR:

  • Each change order should reference the estimate, describe the work, itemize labor and materials, state schedule effects, list attachments, and include dated approval.
  • Show labor, materials, equipment, subcontractor costs, and markup separately, then list the original contract, prior changes, current change, and revised total.
  • For changes above a few hundred dollars, require a signature or electronic signature; smaller residential jobs may accept written approval if the contract permits it.
  • Owner additions often need only written approval and a price, while hidden damage and code corrections call for formal orders when costs or schedules shift.
  • Put the change order number on every related invoice so the client’s bookkeeper can trace each charge to its authorized contract change.
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Table of Contents

The 6 essential elements every change order needs

A change order doesn't need to be fancy. It needs to be complete enough that nobody can argue about it later. Procore's guidance lays out the core fields every usable change order should include, and solo contractors can fill these out from a truck or job site in a few minutes.

  • Project and contract reference: tie the change order to your original estimate number and give it its own sequential number (CO-01, CO-02, and so on).
  • Clear description: say exactly what's changing and where, like "add GFCI outlet, kitchen island, east wall."
  • Itemized cost delta: break out labor, materials, equipment, subcontractor costs, and your markup separately.
  • Schedule impact: state the delay in days or give new calendar dates, plus the reason for the delay.
  • Attachments: list photos, supplier quotes, or sketches by filename, like "photo_2026-06-12_wall.jpg."
  • Approval line: a spot for a signature or e-signature, printed name, and date.

A text message saying "yeah go ahead" is not solid proof. A dated email, a signed PDF, or an e-signature tool gives you something you can point to if a client pushes back weeks later.

Pro Tip: Keep a blank change order template saved on your phone so you can fill one out standing in the client's kitchen instead of promising to "send something later."

Contractor fills out a change order on a phone

A step-by-step process you can use on any job

Most disputes happen because contractors skip steps when they're in a hurry. Following the same order every time keeps you covered, whether you're rewiring a panel or replacing a water heater.

  1. Spot and classify the change. Decide if it's an addition, a deletion, or a modification to the original scope.
  2. Give written notice. Check your contract for any notice window and send a short note saying a change is coming.
  3. Draft the change order. Use the six-element checklist above so nothing gets left out.
  4. Submit it and set a deadline. Give the client a response window and keep a record of when you sent it.
  5. Negotiate and get it signed. Revise the price or scope if needed, then collect a signature or e-signature. Ask for a deposit upfront on larger changes.
  6. Do the work and update your records. Once it's signed, start the job and immediately update your running contract total and invoice.

The Associated General Contractors note that change orders cover any work added to or removed from the original contract, and treating each step as routine, rather than a special event, keeps the paperwork from piling up at the end of a job.

How to price and bill a change order

Price a change order the same way you'd price the original job: break it into labor, materials, equipment, any subcontractor pass-through costs, and your overhead or profit margin. Showing each piece separately makes it easy for a client to see where the money goes instead of staring at one lump number.

  • Set a deposit rule for bigger changes. For example, require a deposit upfront on larger change orders, and write that term right on the CO.
  • Option A, line items on the regular invoice. Works well for small or short jobs, like adding an extra light fixture during an electrical service call.
  • Option B, a standalone invoice. Better for large change orders or clients whose accounts payable department needs a separate paper trail.
  • Option C, adjust a milestone or draw. Use this when the change affects a payment already tied to a project phase.
  • Reference the CO number on every invoice. Writing "CO-01" on the invoice line lets the client's bookkeeper match the charge to the signed approval in seconds.

Never start changed work on a handshake alone, especially on bigger-ticket items. A quick email reply or an e-signature is enough protection for most jobs, and it takes less time than redoing a wall because the client says they never approved it. If you want a faster way to turn an approved CO into a professional invoice, a branded invoice template keeps the format consistent every time.

Exact fields, numbering, and filing habits that prevent disputes

Clean numbering is what makes a final invoice easy to defend. Tie every change order back to the original estimate so anyone reviewing the file can follow the money from start to finish.

  • Numbering example: Estimate #E-2041 becomes CO-01 (ref. E-2041), then CO-02 (ref. E-2041), each showing a running total.
  • Show four numbers on every CO: original contract amount, prior approved change orders, this change order's cost, and the new contract total.
  • Name your files consistently: something like "photo_2026-06-12_wall.jpg, attached to CO-01" so nothing gets lost in a photo roll.
  • Store signed approvals somewhere searchable, whether that's email, a shared drive, or your invoicing software, and keep them for as long as your state requires contract records to be kept.
  • Match invoice numbers to CO numbers so a client can trace any charge back to the approval that authorized it.

An invoice numbering system built around this same logic keeps your records consistent across quotes, change orders, and final invoices.

What counts as approval, and how to make signing fast

A signed change order is the gold standard, but it isn't the only acceptable form of approval. Check your original contract first, since some contracts spell out exactly what counts. Short of a signed form, a clear approval email or a confirmed text thread referencing the CO number can hold up, especially on smaller residential jobs.

  • Use e-signatures for commercial clients or any job running through a property manager or accounts payable department.
  • Insist on a signed or e-signed CO for anything over a few hundred dollars, since verbal approval gets forgotten fast.
  • Document owner-directed changes immediately if the client tells you to start before paperwork is signed, since this protects you if the scope gets disputed later.
  • Set a response window, like two to three business days, and write that deadline right on the change order.

Pro Tip: If a client insists you start before signing, send a follow-up email promptly summarizing exactly what was discussed and the price, so there's still a written trail.

Quick rules on common triggers and timing

Some changes are small enough for a two-line note. Others need a full formal change order. Knowing the difference saves time without cutting corners.

  • Owner requests or additions, like adding a ceiling fan during a remodel, usually need just a quick written approval and price.
  • Hidden conditions, like rotted subfloor found during a bathroom tear-out, call for a formal change order since the scope and cost shift significantly.
  • Inspector or code-required corrections almost always need a formal CO, since the work is often non-negotiable and can affect your schedule.
  • Design clarifications from updated drawings or specs usually fall somewhere in between, so match the paperwork to the size of the cost change.

What keeps the change order process from becoming a bottleneck

The contractors who handle change orders well treat the paperwork like any other short task on the job, not a special event that slows everything down. A habit of filling out the same template every time beats scrambling to remember what was agreed to later.

Keeping a standard set of fields for invoice line items also makes it easier to show a client exactly what a change order added to their bill, rather than burying it in a vague total.

— jaras

Speed up your change order to invoice workflow with Quotewren

We built Quotewren for solo tradespeople who need to create and send invoices without wrestling with spreadsheets. Our branded quotes and invoices help you keep your paperwork organized, include pay links, and send an automated review request once the job wraps up.

  • Create branded quotes and invoices.
  • Add a pay link so clients can pay a change order invoice immediately.
  • Send automated review request follow-ups after the job is complete.

We offer a Free plan to get started, plus Quotewren at $19 per month and Quotewren Crew at $39 per month for busier solo operations. Try the Quotewren free plan today and see how fast a change order can turn into a paid invoice.

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FAQ

Who prepares a change order?

The contractor typically drafts the change order, since they're the one pricing the labor and materials for the new scope. On larger commercial jobs, a project manager or general contractor may prepare it instead, but the client or owner still has to review and approve it before work begins.

What is the difference between an RFI and a change order?

A request for information, or RFI, asks a question about the plans or specs and doesn't change the contract by itself. A change order only gets created once that question, or any other issue, actually changes the scope, price, or schedule of the job.

What happens after a change order?

Once a change order is signed, the contractor updates the running contract total and begins the changed work, referencing the CO number on any related invoice. The American Bar Association notes that a properly approved change order becomes a binding amendment to the original contract.

Does a change order need to be signed?

A signature is the strongest form of approval and the one most contracts require for anything beyond a minor change. Smaller changes sometimes move forward on a written email approval, but checking your original contract language is the only way to know what's required for your specific job.

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