SWIFT ISO 15022 - Code INIR Financial acronyms The entire acronym collection of this site is now also available offline with this new app for iPhone and iPad. Meaning Instruction Irrevocable: The instruction is irrevocable. Usages Message type Field number Tag MT549 (Request for Statement/Status Advice) 17 24B (Reason) MT567 (Corporate Action Status and Processing Advice) 13 24B (Reason Code)