If agent Amy forgot to show up for an open house, what is the term for Sam terminating the listing agreement?

The correct term for Sam terminating the listing agreement in this scenario is referred to as revocation. When an agent fails to fulfill their responsibilities—such as not attending an open house—it can lead to the principal (Sam, in this case) choosing to terminate the relationship, known as a revocation of the agreement.

In this context, revocation indicates that one party is unilaterally ending the agreement due to the other party's failure to perform as expected. Sam has the right to revoke the contract when he deems that Agent Amy's lack of attendance undermines the purpose of the agreement and jeopardizes his property sale.

Other terms mentioned, like mutual consent, would apply if both parties agreed to terminate the listing together, while renunciation can refer to a voluntary relinquishment of a right or privilege, and subrogation is a legal term usually associated with insurance claims and not relevant to real estate listing agreements.