First, the nomination of a guardian in your will (and I assume you mean a guardian for your children, if you pass away) is just your nomination, it's not binding on the court. The natural father will have the "inside track" at getting custody of the children. If someone is to get guardianship, they will have to petition the court to be named guardian. So, for this change only, it might be okay to create a new document that says, "I nominated X as guardian for my children in my will. I have changed my mind. I now wish to nominate Y as guardian." Sign that in the presence of two witnesses, at least one of whom will be able to appear in the guardianship proceeding. Date it. Keep it with your will. Do not make any marks on the original will. You can't change it by marking it up; you may revoke it. That's my suggestion. I haven't done any legal research, this is just an answer on a website. No lawyer-client relationship is created. Estate planning is not that expensive, and you might be able to find a lawyer in your area willing to let you pay over time. A good, lawyer-created estate plan is better, and since you'll be gone when your will needs to "speak," you want it to be right.
Answered on Feb 07th, 2014 at 10:20 PM