The purpose of this API is to retrieve a list of all the guest passes sent from or received by a user. This includes Used, Received, and Available guest passes. You must specify the unique identifier of the guest who is sharing the guest pass guest_id, the item id for which the user wants to transfer to/receive from (default value would be null) instrument_id, the item type (default would be 1. 1: Membership) instrument_type, guest pass credit type (default would be 1. 1: Classes, 2: Visits, 0: Both) credit_type, type of user list the user requested (default would be 0. 0: Both, 1: Receiver, 2:Sender) list_type, and the expand parameter (expand[0]=available, expand[1]=received, expand[2]=used) expand.