What Is a Change Order in Construction?

By Wyatt Cooper · Published October 22, 2026 · 3 min read

Key takeaways

A change order is the signed document that adds, deletes or revises work and states the new contract price and time.
It usually starts as a change order request with a price; it becomes a change order once both sides sign.
Executed change orders raise or lower the contract sum, and every later pay application bills against the revised total.

A change order is a written amendment to a construction contract, on most private jobs signed by the owner and contractor, that changes the scope of work and adjusts the contract price, the contract time, or both. It is how added, deleted or revised work becomes part of the contract, and later pay applications bill against the revised contract sum.

How a change order works

The City of Los Angeles's manual puts it simply: a change order identifies "required changes to the original plans, specifications, or other contract documents", and once scope, cost and schedule are negotiated, "the final change order with the proper signatures becomes a legal amendment to the construction contract". It sorts changes into three causes: changed or unforeseen conditions, errors and omissions, and changes in scope (LA Bureau of Engineering, 20.1).

Federal contracts use the word differently. Under the changes clause, the contracting officer may issue written change orders on its own, including changes "In the specifications (including drawings and designs)" and "In the method or manner of performance of the work", and the price and time are adjusted afterward (FAR 52.243-4). That is closer to what private contracts call a directive; the difference is set out in change order vs. change directive.

Example

Change order #3: add two doors at the break room

Reason: Owner request
Cost of the work: $8,400
GC markup (10%): $840
Change order amount: $9,240
Contract time: +2 days
Original contract sum: $1,250,000
Previous change orders: +$14,500
Contract sum after this change order: $1,273,740

A change order and the contract sum it produces (fictional figures)

The arithmetic: 10% of $8,400 is $840, so the change order is $9,240; $1,250,000 + $14,500 + $9,240 = $1,273,740. How to build the price is in how to price a change order; an owner's checks are in how to review a change order as an owner.

Change order vs. change order request

The documents on the way to a change
Document	Who sends it	Does it change the contract?
Change order request	Contractor or sub	No; it proposes a change and a price
Change directive	Owner, through the architect	Directs the work now; price settled later
Change order	Signed by owner and contractor	Yes

The first step is the change order request, often started by an RFI answer or a field condition.

How it works in Conflo

In Conflo's change orders, each one carries its reason (RFI, owner request, field condition or design error) and can link the RFI that started it. Lines are priced by cost code, the GC sets the markup, days added or saved are recorded, and it goes through GC review and owner approval. Approval executes it, adds a sub's quoted work to their commitment at their cost, and the change flows into pay applications.

A change order waiting on owner approval in Conflo: a grease interceptor upsize from an RFI answer, three cost-coded lines with a 10% markup on the total, two days of schedule impact, the GC review and owner approval steps, and the RFI it came from. — A change order waiting on owner approval in Conflo: cost-coded lines, the markup and the schedule impact.

The bottom line

A change order is the only document that changes what the contract says you will build and be paid.

Price it with backup, state the days, get it signed before you bill it, and keep the log current.

See how change orders work in Conflo

Sources

20.1 Introduction (Construction Change Orders) — City of Los Angeles, Bureau of Engineering, Project Delivery Manual. Read October 22, 2026.
FAR 52.243-4, Changes — Acquisition.gov, U.S. General Services Administration. Read October 22, 2026.

Questions

Who signs a change order?

The owner and the contractor, and on many contracts the architect too. A subcontract change order is signed by the GC and the sub.

Can a change order reduce the contract price?

Yes. Deleted work, a cheaper substitute or an unused allowance can produce a deductive change order that lowers the contract sum.

Should work start before the change order is signed?

Only with written direction. Starting on a verbal request risks not being paid; a change directive or a signed not-to-exceed amount protects both sides.