Delaware Summons Third Party By Defendant is a legal document that is served upon a person or entity that is not a party to a lawsuit, but who may be liable for damages in the lawsuit. This document informs the third party that they have been sued and that they must appear in court to answer questions or to provide testimony. This document is especially important for cases involving personal injury or breach of contract. The Delaware Summons Third Party By Defendant can be divided into two main types. The first is the “Summons and Complaint” which is served upon the third party, and states the details of the complaint and orders the third party to answer it. The second type is the “Summons and Notice of Hearing” which notifies the third party of the date and time of the hearing and provides instructions on how to respond.