Add a Codicil
Revoke the existing clause in the original will that names the executor. Replace by adding a new clause, which makes the change. Known as a codicil, this legal document allows you to make a change while leaving the rest of the will to remain as initially created.
Specify in the codicil exactly which clause(s) in your original will are being amended by the addition of the codicil. State within the codicil that your previous will still stands in all other respects.
Date the codicil so that it is obvious that the amendment was made after you made the original will. Number the codicil, especially if you have made other revisions to your will.
Ask two people to witness you signing the codicil. You must then witness each of their signatures. It is permissible to use different witnesses than those who witnessed you signing the original will.
Provide the newly appointed executor with a copy of your will and codicil. Let your family know who you have appointed to execute the affairs of your estate.
Drafting a New Will
Prepare a new will. If you are making other changes to your will along with appointing a new executor, writing a new will might be a more practical alternative than simply adding a codicil.
Begin the new will with a clause stating that the updated document revokes all previous wills and codicils. Canceling a will does not automatically invalidate a codicil added afterward. If it is your intention to cancel all previous wills and codicils, a newly drafted will must clearly state that fact.
Consider all the situations that have changed since you wrote your last will. Naming a new executor may not be the only revision needed. If it has been more than five years, it may be necessary to revalue your estate.
Sign and date the will. Have at least two witnesses present when you sign the new document.