AH = 17h DS:DX = pointer to a modified FCB of the format: Offset Description 00 drive designator 01 original file name 09 original file extension 11 new file name 19 new extension on return: AL = 00 if file renamed = FF if file not renamed - allows renaming of files with normal attributes - "?" wildcard supported after DOS 2.1, "*" supported by DOS 3.x+