15.1 Preliminary Instruction-Trademark is a formal request for information from a trademark examiner that must be answered in order for a trademark application to proceed. This instruction is issued by the United States Patent and Trademark Office (USPTO) to applicants requesting a trademark registration. It is meant to alert applicants to potential issues with their application that may need to be addressed before the application can move forward. There are two types of 15.1 Preliminary Instruction-Trademark: Official Action and Office Action. Official Action is issued when the examiner finds that the application as submitted is incomplete and needs additional information. Office Action is issued when the examiner finds potential issues with the registration, such as conflicts with existing marks or the mark not being eligible for registration.