20 CFR 217.18: When application is not acceptable.

(a) Not properly signed. The Board will ask the applicant to prepare a corrected application if—

(1) The original application was signed by someone other than the claimant or a person described in § 217.17; or

(2) The signature has been changed; or

(3) The signature is not readable or does not appear to be authentic.

(b) Incomplete or not readable. The Board will ask the applicant to prepare a supplemental application with certain items completed if—

(1) Any entries on the application are not readable or appear to be incorrect; or

(2) An important part of the application was not completed.

(c) Obtaining corrected application. If an application is not properly signed, the applicant must prepare a new application with a corrected signature. If the Board receives the corrected application within 30 days after the applicant is asked to prepare it, the Board will use the filing date of the original application to pay benefits. If the Board receives the corrected application more than 30 days after the notice to the applicant, the Board will use the filing date of the corrected application to pay benefits.