When an offer is made your agent will work with you in making sure that you are getting the best possible deal, taking into consideration your needs and wants. They will discuss any contingencies the buyer wants and discuss your best course of action.
If an offer is accepted your agent will help you out until the final closing. They will make sure that the buyer is fulfilling their contractual obligations and make sure that you are doing all that you need to do to transfer ownership of your home.