Appointment of Agent.
If an agent negotiates your contract, then it will very likely contain what is known as the "agency clause." This is especially true of agency relationships that are not covered by a written agency agreement: in these cases, the agency clause in the publishing contract enshrines the agreement between author and agent with respect terms such as the agent's compensation, method of payment, and length of the agency relationship, etc. A typical agency clause may look like this:
Author hereby authorizes Agent to collect and receive on behalf of Author all sums of money due under this Agreement, and receipt of such monies by Agent shall be a good and valid discharge of Publisher's obligations to make such payments to Author. Agent is authorized and empowered to act on behalf of Author in all matters in any way arising out of this Agreement.