How to document changes to a business contract in Australia
Record agreed changes to scope, price and timing with a clear variation record, linked contract versions and practical questions for your legal adviser.
Reviewed by lm ·
Short answer: Start with the existing contract and its variation procedure. Write down exactly what is changing, what stays the same, when the change takes effect and how it affects price, scope and timing. Obtain the agreement and approvals the circumstances require, then keep the change record with the original contract. A clear record is useful evidence; it does not, by itself, establish that a variation is legally effective.
This is general information for Australian businesses managing ordinary service arrangements, not advice on a particular contract. Building work, employment, leases, franchises and financial services can require different treatment. Have an Australian lawyer check legal effect, authority and any signing requirements before relying on a material change.
First identify what the parties are changing
A variation changes a contract already in place. It is different from an unaccepted request for extra work. Government guidance recommends recording variations in writing and having both parties sign, while recognising that changes can also be discussed or agreed verbally. It describes separate documents, handwritten amendments and email or letter records as ways to document changes.[1]
Do not interpret that guidance as a rule that every email is enough, or that every unsigned change is ineffective. Check your actual contract and ask for advice if the parties have already acted on an informal request.
Locate the signed agreement, schedules, statements of work and earlier variations. Then identify the clause or schedule affected. If you are unsure which document governs the work, resolve that uncertainty before issuing another “final” version. Awelle’s service agreement guide provides context on scope and variation provisions; it does not decide the effect of your existing agreement.
Use one change record, not a scattered email history
The following is an administrative checklist, not a ready-to-sign legal instrument.
| Record | What to include |
|---|
| Contract identity | Parties’ legal names, agreement date and the exact schedule or clause being changed. |
| Change requested | Existing position, proposed replacement and any work expressly excluded. |
| Commercial effects | Price and GST treatment, payment milestones, delivery dates, dependencies and acceptance criteria affected. |
| Timing | Proposed effective date, separately from the date each party actually agrees or signs. |
| Status and authority | Who requested it, who can approve it, outstanding questions and evidence of agreement. |
| Document trail | Original agreement, earlier changes, marked-up proposal and the final agreed record kept together. |
Government guidance specifically recommends describing the change and its effect on scope, cost, timeline and date of effect.[1] Also ask whether the proposal affects insurance, intellectual property, confidentiality, liability or connected agreements. Those questions belong in the review rather than being silently left to the person updating an invoice.
Example: an extra service is not just a new price
Hypothetical: A design studio is engaged to produce a brochure. The customer later asks for a presentation deck using the same material. The studio’s record should identify the additional deliverable, number of revision rounds, fee, delivery dependency and whether the original brochure deadline changes.
Label the initial record “proposed”, not “agreed”. Keep the customer’s response with the proposal. If work has already started, record the real sequence and ask an adviser what the communications and conduct mean. Do not backdate signatures to make the file look orderly.
Check one-sided change powers separately
A clause allowing only one party to vary terms is among the examples of potentially unfair terms in the Australian Consumer Law. It is not automatically unfair merely because it appears in that list. The statutory test considers imbalance, legitimate interests and detriment, with transparency and the contract as a whole also relevant.[2]
The ACCC explains that the reforms commencing on 9 November 2023 apply to standard form contracts made or renewed from that date and to terms varied or added from that date. Ask your lawyer which rules apply to the specific contract and change. Do not use a variation as a reason to assume every older term has been approved or replaced.[3]
Before you treat the change as settled
- Check that both parties are working from the same proposal.
- Resolve any mismatch between the change record and a purchase order or revised schedule.
- Confirm the agreement process and signatory authority with the appropriate adviser.
- Keep original evidence; circulate the agreed operational instructions to those delivering and paying for the work.
- Update your working schedule only when the change status is clear.
Is an email enough?
It may help document what was agreed: government guidance includes emails and letters with a response showing agreement. Whether the exchange creates an effective variation depends on the contract and circumstances. Ask for advice where there is uncertainty about formalities, authority or what the response accepts.[1]
Do I need a variation agreement or a deed?
Do not choose only by document title. Give your lawyer the original agreement and proposed change and ask which form, consideration and execution requirements apply. This article does not resolve that legal question.
Next step: Prepare the change record and missing-information list before seeking advice. For an overview of Awelle’s offering, see Awelle for business owners. Awelle’s contract library is lawyer-authored; AI organises that material. That is not a guarantee that a proposed variation suits your transaction.
Sources
- business.gov.au — Prepare a contract, section 13, “Document contract variations”. Australian Government; accessed 12 October 2026. Publication/update date not established from the extracted page.
- Competition and Consumer Act 2010, Schedule 2 (Australian Consumer Law), sections 23–27, especially sections 24 and 25(d). Federal Register of Legislation; compilation 167, 16 September 2026; accessed 12 October 2026.
- ACCC — Contracts, “Changes to the law on unfair contract terms”. Accessed 12 October 2026; publication/update date not established from the extracted page.