A submission release is an agreement in which an author agrees that he will not be entitled to compensation merely because the party to whom he has submitted the work produces a work that is similar to their submission. Submission releases often require the author to make other guarantees which protect the interests of the agency/producer.
Submission release forms are less common in the theater industry than in film and television, but they exist and are used primarily by corporate producing entities with regard to unsolicited materials. An author should not be asked to sign a submission release when a producer has solicited their submission.