The USPTO provides notice for reexamination requests filed under 35 U.S.C. 302 through publication in the Official Gazette. This is particularly important when direct communication with the patent owner is not possible. MPEP 2230 states: "The publication in the Official Gazette of (A) the notice of the filing of a request for reexamination filed under 35 U.S.C. 302... will serve as constructive notice to the patent owner in such an instance." This means that even if the USPTO cannot reach the patent owner directly, the publication of the reexamination request in the Official Gazette serves as legally sufficient notice, allowing the reexamination process to proceed. To learn more: reexamination request 35 U.S.C. 302 Official Gazette constructive notice USPTO procedure