Washington Supplemental Subpoena Request Form is a legal document used to obtain documents or testimony from a person or entity located in the State of Washington for use in a court of law. It is issued by the court in which the case is pending and requests that the person or entity provide the requested documents or testimony. There are two types of Washington Supplemental Subpoena Request Forms: a Subpoena Ducks Cecum and a Subpoena Ad Testificandum. A Subpoena Ducks Cecum requires the requested person or entity to bring certain documents or other tangible evidence as specified in the subpoena. This type of subpoena is often used to gather evidence for a case. A Subpoena Ad Testificandum requires the requested person or entity to appear in court to testify. This type of subpoena is typically used to obtain testimony from an expert witness or other person with knowledge relevant to the case. In both cases, the Washington Supplemental Subpoena Request Form must be served on the requested person or entity, typically by a process server. The form must include information about the court, the case, and the documents or testimony requested. It must also include instructions for the requested person or entity about how to respond to the subpoena.