When do amendments become effective in patent reexamination?

Amendments proposed during patent reexamination do not become legally effective immediately. According to MPEP 2234:

“Although the Office actions will treat proposed amendments as though they have been entered, the proposed amendments will not be effective until the reexamination certificate is issued and published.”

This means that while amendments are considered for examination purposes, they only become officially part of the patent when the reexamination process is complete and a certificate is issued. This delay in effectiveness ensures that the public is properly notified of changes to the patent through the publication of the reexamination certificate.

All Amendments Must Be Fully Presented MPEP 2234 Required
Amendments Required for Merged Reexamination Proceedings MPEP 2234 Informative
Amendments Must Comply With Specific Requirements for Reexamination MPEP 2234 Required
Claims Must Follow Highest Numbered Claim During Reexamination MPEP 2234 Prohibited
Claims and Descriptions Must Be Fully Presented For Any Amendment MPEP 2234 Required