When you need to perform a task or action again, there are various synonyms for the phrase 'do a repeat' that you can use. Some of these include repeating, redoing, duplicating, replicating, reiterating, reproducing, and copying. Each of these words can be used interchangeably with 'do a repeat' to convey the idea of repeating something. For instance, instead of saying 'do a repeat,' you can choose to say 'redo,' 'duplicate,' or 'copy' to convey the same idea. These synonyms are useful for avoiding repetition in your writing or speech and adding variety to your vocabulary.