Sure, within reason for the setting. There is a reason that their patron has them in the first place, and I'm betting until the warlock did the betrayal, the reason was something along the lines of "can't act directly in the mortal realm" or somesuch. As long as this isn't a 'god's wrath falls, warlock dies' moment, there is a lot of room for fun in how a warlock might have to start dodging other warlocks or mystical beings the patron can act through.