MPEP § 402.05(b)
*****
See MPEP § 402.07 for revocation of a power attorney by the assignee. Form PTO/SB/81 may be used to revoke a power of attorney in an application filed before September 16, 2012. See also MPEP § 402.02(b).
If the power of attorney was granted by the originally named inventive entity and an added inventor pursuant to § 1.48 does not provide a power of attorney consistent with the power of attorney granted by the originally named inventive entity, the addition of the inventor results in the loss of that power of attorney upon grant of the § 1.48 request. This provision does not preclude a practitioner from acting pursuant to 37 CFR 1.34, if applicable. See MPEP § 402.04 for information pertaining to acting in a representative capacity.
When an original power of attorney is filed giving power of attorney to attorneys A, B, and C, and the same principal subsequently files another power of attorney, giving power of attorney to D without revoking all prior powers of attorney, the subsequently filed power of attorney will be treated as a revocation of the original power of attorney. Similarly, if the applicant signed the original power of attorney, and an assignee of the entire interest of the applicant later takes action and files a new power of attorney, the original power of attorney is revoked and replaced by the power of attorney filed by the assignee. In addition, if a power of attorney is given to the practitioners associated with a Customer Number, and a (second) power of attorney is later received giving power of attorney to patent practitioners associated with a different Customer Number, the second power of attorney will be processed, with the first Customer Number being replaced with the second. The power of attorney to the practitioners associated with the first Customer Number is automatically revoked in this situation. In all of these situations, the most recently filed power of attorney will control.
A nonsigning inventor may subsequently join in a pre-AIA 37 CFR 1.47 application by submitting an oath or declaration under pre-AIA 37 CFR 1.63. However, even if the nonsigning inventor joins in the application, he or she cannot revoke or give a power of attorney without agreement of the pre-AIA 37 CFR 1.47 applicant.