Are substitute specifications allowed in reissue applications or reexamination proceedings?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

No, substitute specifications are not permitted in reissue applications or reexamination proceedings. This is explicitly stated in 37 CFR 1.125(d):

A substitute specification under this section is not permitted in a reissue application or in a reexamination proceeding.

This restriction is important to maintain the integrity of the original patent document in these special proceedings. Applicants and practitioners should be aware of this limitation when considering how to make amendments or changes to the specification in reissue applications or reexamination proceedings.