188.8.131.52.1 RopFreeBookmark ROP Request Buffer
BookmarkSize (2 bytes): An unsigned integer that specifies the size, in bytes, of the Bookmark field.
Bookmark (variable): An array that specifies the bookmark to be freed. The bookmark MUST be one that was returned by a previous RopCreateBookmark ROP request ([MS-OXCROPS] section 184.108.40.206). The bookmark MUST NOT have been previously freed using the RopFreeBookmark ROP.