Warm Call is the process or act of calling or visiting a sales prospect with whom the sales professional has had a prior contact such as during an event or via a referral. Warm calling is the solicitation of a potential customer with whom a sales representative in particular, or his firm in general, has had prior contact. … You don’t have to sell to the prospect during a warm call; in fact, it may be better to use it to set up an appointment or virtual meeting instead.