A reissue application is an application that is filed to correct an error in a patent that has not expired. See 35 USC 251 [PDF viewer required]. The error must have been made without any deceptive intention and must be an error that renders the patent wholly or partly inoperative or invalid. See, for example, MPEP 1410, 1410.01, and 1411.
Pay maintenance fees and learn more about filing fees and other payments
Notices of possible system outages