California Code, Civil Code - CIV § 2079.23

(a) A contract between the principal and agent may be modified or altered to change the agency relationship at any time before the performance of the act which is the object of the agency with the written consent of the parties to the agency relationship.

(b) A lender or an auction company retained by a lender to control aspects of a transaction of real property subject to this part, including validating the sales price, shall not require, as a condition of receiving the lender's approval of the transaction, the homeowner or listing agent to defend or indemnify the lender or auction company from any liability alleged to result from the actions of the lender or auction company.  Any clause, provision, covenant, or agreement purporting to impose an obligation to defend or indemnify a lender or an auction company in violation of this subdivision is against public policy, void, and unenforceable.