MPEP 2609

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2609 - 2600 Optional Inter Partes Reexamination

2609 Inter Partes Reexamination [R-7]

....

The basic characteristics of inter partes reexamination are as follows:

(A) Any third party requester can request inter partes reexamination at any time during the period of enforceability of the patent

(for a patent issued from an original application filed on or after November 29, 1999);