What is a reissue application and when is it used?

A reissue application is a type of application used to correct an error in an issued patent that renders the patent wholly or partly inoperative or invalid. It is governed by 35 U.S.C. 251 and 37 CFR 1.171-1.179. Reissue applications are typically filed when the original patent claims are too narrow or too broad, or when there are other errors that affect the scope or validity of the patent. For more information on reissue applications, refer to MPEP 1401.