Washington Provider's Request for Adjustment (WPA) is a form used by providers in Washington State to submit a request for reimbursement adjustment due to a variety of reasons. These reasons include billing errors, incorrect coding, or other overpayment issues. The WPA is submitted by providers to the Washington State Health Care Authority (HCA) to request an adjustment to an existing claim or to report an overpayment for prior services. WPA forms can be submitted electronically or by paper. There are three different types of WPA forms: 1. Standard WPA Form: Used to request an adjustment to an existing claim or to report an overpayment for prior services. 2. Provider Overpayment Refund Form: Used to report and refund any overpayment of a provider that has occurred. 3. Hospital Outpatient Services Overpayment Refund Form: Used to report and refund any overpayment of a hospital outpatient service that has occurred.