One of the oldest principles of estate planning law is that people can always change their minds about what to do in their wills. All they need to do if they want to do something different, is create a new will reflecting their new desires.
It is best to destroy any copies of the old will. However, that is not strictly necessary. There are some times when people cannot change their minds about their wills.
One example is when someone has entered into a valid contract to leave something specific to someone else.
A recent case concerning that idea was discussed by the Wills, Trusts, & Estates Prof Blog in "Surrogate's Court Sets Aside Fraudulent Conveyance Violative of Contract to Make a Testamentary Disposition."
This type of contract is called a contract to make a testamentary disposition, which is legalese for an enforceable promise to leave someone something in a will.
The idea is very simple. If you sign a contract to bequeath a piece of property to someone and the other party to the contract performs his or her duties under the contract, then you cannot change your mind later and rewrite your estate plan to do something different.
While this specific issue does not come up all that often, it is important to understand that contract responsibilities survive your death and supersede your estate plan.
Let an elder law attorney know if you are contractually obligated regarding a specific asset, so your estate plan can be written accordingly.
Reference: Wills, Trusts & Estates Prof Blog (Dec. 16, 2017) "Surrogate's Court Sets Aside Fraudulent Conveyance Violative of Contract to Make a Testamentary Disposition."