If you submit a review for a Pro and it is then approved, the Pro will have 48 hours to respond. This can be a chance to say thanks, or an opportunity to address any problems which you might have had with their service.
If the review has a rating of three stars or less, it will not appear publicly until the 48 hours have passed. During this time, the Pro may want to try and address your concerns. For example, if you feel as though they have not completed your job to a high standard, you may want to schedule a further site visit. Once the 48 hours pass, you will have the option to have your review remain on their page or to have it archived.