Everyone has the right to create a last will and testament that dictates their wishes about what will happen to their property once they die. Many people create a will during their lifetime, but at one time or another, decide to make changes or corrections to the provisions in it. While creating a will with the aid of a lawyer is usually in your best interest, you can change your will yourself, provided you comply with state laws.
Find out the state requirements. Anyone can create a valid will without an attorney, as long as they meet their state's requirements. Changing a will can similarly be done without an attorney, but you have to first know what the state requires. Usually, states require people writing or changing a will to be at least 18 years old, be of sound mind, make the will or change in writing, sign the will, and have the will witnessed and signed by two witnesses without a stake in the will. However, there are differences among the states.
Decide on a codicil or a new will. The simplest way to make changes to a will is the addition of a codicil. These are provisions that are added to a will after it is created and are incorporated into the will by reference or physical attachment. Codicils are less frequently used today because it is usually much easier to simply make a new will with the new changes incorporated in it.
Write the changes down. No matter if you use a codicil or create a new will, you'll have to write the terms down. You probably don't need any special format (though you'll have to check your state's law), but you will need to have the change in writing.
Sign, date and witness the changes. Once you've made the changes, you should sign and date the will (or codicil) and have it signed and witnessed by two other people. These should ideally be people who do not stand to benefit if you die, as they are uninterested parties and will serve as better witnesses should the validity of the will be questioned. Make sure all witnesses include their addresses in their signature block.