1505.02(c) Amendments to Marks 
In an application under §1 or §44, if the applicant proposes to amend the mark after publication, the amendment is not a material alteration of the mark, and the specimen of record or foreign registration (if applicable) supports use of the mark as amended, the USPTO will approve the amendment and will not republish the mark. If the applicant proposes to amend the mark and the amendment represents a material alteration to the mark, the USPTO will not approve the amendment. See 37 C.F.R. §2.72; TMEP §§807.13-807.13(b), 807.14-807.14(f).
The mark in a §66(a) application cannot be amended. TMEP §807.13(b).