Return of Purchase Order and Request for Advance Payment are documents used in commercial transactions to facilitate the return of goods and services or request a payment in advance of the delivery of goods and services. The Return of Purchase Order is used when a buyer needs to return goods or services that have already been purchased and the Request for Advance Payment is used when a seller requires a payment be made prior to the delivery of goods or services. There are two main types of Return of Purchase Order: credit memo return and return with replacement. A credit memo return is when a buyer returns goods or services and receives a credit to their account in exchange. A return with replacement is when a buyer returns goods or services and receives a replacement product or service in exchange. There are two main types of Request for Advance Payment: cash advance and deposit. A cash advance is when a seller requires a payment before goods or services are delivered. A deposit is when a seller requires a partial payment prior to the delivery of goods or services. The remaining balance is paid upon delivery.