You can make changes to your last will or revoke your last will at any time. However, there are some very important rules to follow. One way to make changes to a last will is to make a codicil, which is an amendment to a last will. Another way is to make an entirely new last will that states that the new last will revokes and takes precedence over any older last wills. A codicil is a separate document and must be signed and witnessed just like a regular last will. Because of these formalities, it may be easier to make an entirely new last will.
You should not make any changes on your will after it has been signed. If you cross out a person's name or add a clause, your change will not be valid and your entire will might become invalid.
If you want to change something in your will, but cannot get to a notary to have it self-proved, you can execute a codicil that is witnessed, but not self-proved. As long as it is properly witnessed, it will legally change your will. The witnesses will have to later sign an oath if the codicil was not self-proved. Because of the possibility of error, having the codicil notarized is the most common way to change a last will.