Absolutely, a Will or Trust can be modified at any time, but is generally only changed due to changes in life events such as a change in beneficiaries, change in children's status, Executor status, or change in your marital status. Changes can be accomplished with a document called a codicil, or by revoking the Will or Trust and having a new one drafted. Codicils must be executed with the same formalities of a Will, i.e. two witnesses and a notary.