WordNet (r) 3.0 (2006):

account representative
    n 1: someone in charge of a client's account for an advertising
         agency or brokerage or other service business [syn:
         account executive, account representative, registered
         representative, customer's broker, customer's man]

The Free On-line Dictionary of Computing (30 December 2018):

Account Representative

    A person in a company who identifies new accounts,
   analyses customer needs, proposes business solutions,
   negotiates and oversees the implementation of new projects.

   (2004-03-08)