Once the initial Trust document is created, changes require either an Amendment or a Restatement (i.e. a new Trust).
The amendment or restatement should comply with the same execution requirements of the Trust itself, should be done in writing, and should be signed by the donor with his or her signature notarized.
(However, if the Trust document is to remain the same but only the property which is transferred to the trust changes either by way of additions or subtractions, the trust document itself does not need to be revised.)
For do-it-yourself option to easily create and manage a Trust, see Standard Legal’s Living Trust legal forms software.