Del. Code tit. 10, § 3917

In any action brought upon any deed, bond, bill, note or other instrument of writing, a copy of which has been filed with the complaint, the plaintiff may specifically require the defendant or defendants to deny the allegation that the defendant’s or defendants’ signature appears on the instrument by affidavit filed with the answer, by the specific notation of the need for denial by affidavit within the paragraph alleging that the signature of defendant or defendants appears upon the instrument. Any defendant so answering shall specifically deny that the defendant’s signature appears on the instrument. Where plaintiff has complied with this section, failure of any defendant to file an affidavit with the answer shall be deemed an admission of the signature as alleged.