Can claim scope be enlarged during ex parte reexamination?

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, the scope of a claim cannot be enlarged during ex parte reexamination. This is one of the basic characteristics of ex parte reexamination as stated in MPEP 2209:

“(G) The scope of a claim cannot be enlarged by amendment;“

This limitation ensures that patent owners cannot use the reexamination process to broaden their patent rights beyond what was originally granted. Amendments during reexamination are typically limited to narrowing the scope of claims or clarifying language to distinguish over newly cited prior art.