MPEP § 2236
Reexamination requests are generally assigned to the Central Reexamination Unit (CRU) art unit which examines the technology (Chemical, Electrical, Mechanical, etc.) in which the patent to be reexamined is currently classified as an original classification. In that art unit, the CRU Supervisory Patent Reexamination Specialist (SPRS) will assign the reexamination request to a primary examiner, other than the examiner who originally examined the patent application (see "Examiner Assignment Policy" below), who is most familiar with the claimed subject matter of the patent. In an extremely rare situation, where a proceeding is still in a Technology Center (TC) rather than the CRU, the reexamination may be assigned to an assistant examiner if no knowledgeable primary examiner is available. In such an instance a primary examiner must sign all actions, conference all actions with a SPRS or manager and another examiner, and take responsibility for all actions taken.
It is the policy of the Office that the CRU SPRS will assign the reexamination request to an examiner different from the examiner(s) who examined the patent application. Thus, under normal circumstances, the reexamination request will not be assigned to a primary examiner or assistant examiner who was involved in any part of the examination of the patent for which reexamination is requested (e.g., by preparing/signing an action), or was so involved in the examination of the parent of the patent. This would preclude assignment of the request to an examiner who was a conferee in an appeal conference or panel review conference in an earlier concluded examination of the patent (e.g., the application for patent, a reissue, or a prior concluded reexamination proceeding). The conferee is considered to have participated in preparing the Office action which is preceded by the conference.
Exceptions to this general policy include cases where the original examiner is the only examiner with adequate knowledge of the relevant technology to examine the case. In the unusual case where there is a need to assign the request to the original examiner, the assignment must be approved by the CRU Director, and the fact that such approval was given by the CRU Director must be stated by the examiner in the decision on the request for reexamination or must be indicated with the CRU Director’s signature affixed at the end of the order or action.
It should be noted that while an examiner who examined an earlier concluded reexamination proceeding is generally excluded from assignment of a newly filed reexamination, if the earlier reexamination is still ongoing, the same examiner will generally be assigned the new reexamination.
Should a reexamination be inadvertently assigned to an "original examiner" (in a situation where the TC or CRU Director’s approval is not stated in the decision on the request), the patent owner or the third party requester who objects must promptly file a paper notifying the Office. Any paper notifying the Office of an assignment to an "original examiner" must be filed within two months of the first Office action or other Office communication indicating the examiner assignment, otherwise reassignment based on such objection will not be considered. Reassignment of the reexamination proceeding to a different examiner will be addressed on a case-by-case basis. In no event will the assignment to the original examiner, by itself, be grounds for vacating any Office decision(s) or action(s) and "restarting" the reexamination.
A situation may arise where a party timely (i.e., within the two months noted above) files a paper notifying the Office to the assignment of a reexamination to the "original examiner," but that paper does not have a right of entry under the rules. An example of this is where a third party requester becomes aware of the assignment to the "original examiner" via that examiner signing the order for reexamination, and the patent owner does not file a statement under 37 CFR 1.530. In that situation, the third party requester cannot file a reply under 37 CFR 1.535, and thus has no way to present the paper directed to the examiner assignment (no right of entry under the rules). In situations where a paper directed to the examiner assignment has no right of entry under the rules, the Office may waive the rules to the extent that the paper directed to the examiner assignment will be entered and considered.