it could be for either. I think it's more often an offer for representation, but some agents will call for an R&R - though usually, in that case, they're pretty serious about potentially repping you, if you do make their requested revisions. But you won't know if it's an offer of representation until you actually talk to them, so definitely wait until after the phone call to let other agents know, if that's what it is. If you are offered representation, it's totally acceptable to ask for some time to consider the offer (this can be anywhere from a week to two weeks), and it would be during this time that you email other agents, let them know you've been offered rep and that they have (X) amount of days to get back to you.