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Family

Can I change a separation agreement later in New Brunswick?

TSL Written by the Treadstone Law Team· Updated November 6, 2026

This answer covers the law of New Brunswick.

Yes, you can usually change a separation agreement, but how depends on whether the other person agrees. If you both agree, any change must be in writing, signed by the people bound and witnessed, just like the original agreement. Informal changes are risky because the formal rules apply to amendments too.

If the other person will not agree, your options are narrower, and which ones apply depends on which part of the agreement is involved. A valid signed and witnessed agreement on property prevails over a conflicting provision of the Marital Property Act. The court can set aside a support provision or a waiver of support where it results in unconscionable circumstances. It may also disregard a provision of a domestic contract if a spouse signed without independent legal advice and applying it would be inequitable in all the circumstances.

Children's issues are treated differently from money. A court can make a parenting order on application by a parent, and the court looks only at the child's best interests. What you can change, and how, depends on your agreement's wording, so have a lawyer review it before you act.

Key takeaways

  • If you both agree, an amendment to a separation agreement must be in writing, signed by the parties to be bound, and witnessed.
  • A valid signed and witnessed agreement on property generally prevails over a conflicting provision of the Marital Property Act, so it is hard to undo.
  • The court can set aside a support provision or a waiver of support where it results in unconscionable circumstances.
  • Whether and how your agreement can be changed depends on its wording and your facts, so have it reviewed before you act.
This is general information, not legal advice. It doesn’t create a lawyer–client relationship, and the rules can change. For advice on your situation, a Treadstone family lawyer can help.

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Sources

Links go to official government, court and regulator pages. The law changes — confirm you are reading the current version.

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