Creating a retainer agreement can be an essential part of protecting both parties in any professional relationship. This client Retainer Agreement is for ongoing service agreements between a client and consultant or contractor.A fee retainer agreement a type is a contract where a client or customer pays in advance for professional services and work product to be specified later. In-Text Table 1 – Summary of ICs and ECs. I,. , "client," retain. ,. Types of Partition Actions.