The power of attorney is void as your father is now deceased. Trusts are not probated documents, so it should be sufficient to provide the co-trustee with a notarized resignation notice so that the remaining co-trustee can still conduct her duties on behalf of the trust without your continued consent. The terms of trust agreement should have an article specifying the process for how trustees are to withdraw.
I would supplement that if you are trying to remove yourself as power of attorney and co-trustee for your mother, it may be a good time to have your mother make a new power of attorney (poa's should be updated frequently anyway) and review your mother's trust in light of your father's passing.
JASON C. HUNTER
Salt Lake City Office:
299 South Main Street, Suite 1710
Salt Lake City, UT 84111
1104 Country Hills Drive, Suite 305
Ogden, UT 84403
The power of attorney is terminated at the time your father died. As Trustee, you can resign by writing a letter and delivering it to the other co-trustee and all of the trust beneficiaries. At the same time, you should ask them to sign something acknowledging your resignation and acknowledging that you have done a good job as co-trustee and that they WAIVE all claims against you for the services you have rendered to the trust. An attorney could prepare ironclad documents for this purpose, but if you choose to not use an attorney, I suppose you can do it yourself . . . but you won't be protected as well as if you had professional assistance.