From Longman Dictionary of Contemporary Englishhave something off pathave something off patBritish English, have something down pat American EnglishKNOW something to know something thoroughly so that you can say it, perform it etc immediately without thinking about it SYN (off) by heart → pat
Examples from the Corpus
have something off pat• She only had to repeat the lines once or twice, and she'd have them down pat.• Like most politicians he had all his answers off pat, but he didn't have anything particularly new or interesting to say. 