How to properly fill out the Arizona Association of Realtors Resale Purchase Contract using Dotloop. Ordering activities shall establish the BPA with the schedule contractor(s) that can provide the supply or service that represents the best value.A blanket purchase agreement is a simplified method of filling anticipated repetitive needs for supplies or services. A blanket order can also be used in association with a contract that's already in place or with a new agreement once negotiations are complete. Residential Resale Transaction Forms. To create a new Blanket PO from scratch, click the Documents drop-down menu in the Navigation bar, hover the mouse over POs, and select New. This particular contract dictates the purchase and sale of real estate in Phoenix and throughout the state.