Can a Prenup Be Changed or Revoked?

 Posted on May 18, 2026 in Prenuptial & Postnuptial Agreements

Many people think prenuptial agreements are permanent once they are signed. In reality, couples can often change or revoke a prenup later if both spouses agree. A couple may build a business together, have children, inherit property, or simply decide their original agreement no longer reflects their marriage.

If you are considering changing a prenup in 2026, you’ll need to know the basics about how Illinois law treats these agreements so you’ll have a better idea of what you need to do. An Aurora, IL prenup agreement attorney can help you review your current prenup and negotiate changes that protect your interests.

How Can a Prenup Be Changed After Marriage?

In Illinois, spouses can change a prenuptial agreement after marriage if both parties agree to the changes in writing. This is commonly done through either:

• An amendment to the existing prenup

• A postnuptial agreement

A postnuptial agreement works similarly to a prenup, but it is signed after a couple is already married. Some couples choose a postnup instead of modifying the original agreement because it allows them to completely update the terms in one document.

If you do decide to change your existing prenup, you should know that under the Illinois Uniform Premarital Agreement Act (750 ILCS 10/6), a premarital agreement may be amended or revoked only by a written agreement signed by both spouses. That means you can’t just change your prenup on your own. Your spouse has to completely agree. 

This also means verbal agreements are generally not enough. Even if both spouses "understand" that certain terms no longer apply, the court will look at the written agreement itself. Verbal agreements are hard to prove, especially if a divorce is later hotly contested and either spouse has a reason to be dishonest. 

Why Would a Couple Change Their Prenup?

There are many reasons couples decide to change a prenup after they get married. Common examples include:

• One spouse starts a successful business

• The couple has children

• One spouse stops working to raise children

• One spouse receives a valuable or sentimental inheritance 

• The couple buys property together

• One spouse’s income changes dramatically

• The original prenup feels unfair years later

In some marriages, couples sign prenups while they are young and have relatively few assets. Ten or fifteen years later, their financial lives may look completely different.

Does a Prenup Modification Need To Be Fair?

Illinois courts closely examine changes to prenups and postnuptial agreements in a later divorce, especially if one spouse claims they were pressured into signing. If there are questions about whether a prenup should be enforced, a court may look at factors such as:

• Whether both spouses had their own attorney

• Whether each spouse fully disclosed their finances

• Whether either spouse was pressured or manipulated

• Whether one spouse had enough time to review the agreement

• Whether the terms are extremely one-sided

Postnuptial agreements sometimes receive even greater scrutiny than original prenups because spouses already have legal and financial responsibilities to one another during marriage. For example, imagine one spouse suddenly demands a major financial concession while threatening divorce unless the agreement is signed immediately. A court may question whether the agreement was truly voluntary.

One way to prevent unfair prenuptial or postnuptial agreements is to make sure you work with your own attorney. Even if you trust your spouse completely, working with someone who really understands Illinois law and how these contracts are enforced is a good idea. 

Can a Prenup Be Completely Revoked?

Couples can revoke a prenup entirely if they both agree. In some cases, spouses simply decide they no longer want a premarital agreement setting the terms of their marriage. They may sign a written revocation stating that the original prenup is canceled and no longer enforceable.

However, people need to be cautious about casual or even serious conversations to do away with a prenup. Simply ignoring a prenup for years does not revoke it. A formal written revocation is usually the safest approach. Without clear written documentation, it is easy for there to be serious arguments over whether the prenup still applies during divorce proceedings.

When Is a Prenup Invalid in Illinois?

Even if a prenup was never formally revoked, a court may still refuse to enforce it under certain circumstances. Under Illinois law, a premarital agreement may be unenforceable if:

• It was not signed voluntarily

• One spouse was under duress

• Financial disclosures were incomplete or dishonest

• The agreement was unconscionable when signed

• The document was not properly executed in writing

Courts do not invalidate prenups simply because one spouse later regrets signing the agreement. However, they may intervene if the process itself was unfair or deceptive.

Can a Judge Ignore Just the Spousal Support Waiver in a Prenup?

Illinois courts may decide not to enforce a waiver of spousal maintenance if enforcing it would create extreme hardship for one spouse. This issue sometimes comes up after major life changes that neither spouse anticipated when the agreement was signed. For example, a spouse who develops a serious medical condition years later may argue that enforcing a strict maintenance waiver would be unfair under the circumstances.

Should Both Spouses Hire Attorneys When Changing a Prenup?

Technically, you are not legally required to have separate attorneys when modifying or revoking a prenup. However, separate legal representation can make the agreement much more difficult to challenge later.

An attorney will review your existing agreement with you and explain any risks to the changes you want. They can help you write the revisions using enforceable language. If you need financial disclosures, an attorney can help you make sure they are complete. And, most importantly, if there are unfair or problematic terms, an attorney representing your interests, and your interests alone, can point those out. 

Call an Aurora, IL Prenup Agreement Lawyer Today

Whether you want to modify, revoke, or enforce a premarital agreement, you need a good lawyer. Our Kendall County, IL family law attorneys can help you protect your finances and prepare agreements that stand up in court if necessary. Call The Law Office of Matthew M. Williams, P.C. at 630-409-8184 today for a free consultation.