Del. Code tit. 6, § 2715

No action shall be brought to charge the personal representatives or heirs of any deceased person upon any agreement to make a will of real or personal property, or to give a legacy or make a devise, unless such agreement is reduced to writing, or some memorandum or note thereof is signed by the person whose personal representatives or heirs are sought to be charged, or some other person lawfully authorized in writing, by the decedent, to sign for in the decedent’s absence. This section shall not apply to any agreement made prior to May 1, 1933.