1604.17(b) Correcting Deficiencies in Affidavits or Declarations Filed During the Grace Period 
If the affidavit or declaration is filed during the six-month grace period under §8(a)(3) of the Act, 15 U.S.C. §1058 (a)(3), deficiencies may be corrected, after notification from the Office, before the expiration of the grace period without paying a deficiency surcharge, or after the expiration of the grace period with the deficiency surcharge required by §8(c) of the Act, 15 U.S.C. §1058(c).
Deficiencies must be cured within six months of the issuance date of the Office action. 37 C.F.R. §2.163(b); see TMEP §1604.16.