(a) An application for registration on the Principal Register under section 1(a) or 44 of the Act may be changed to an application for registration on the Supplemental Register and vice versa by amending the application to comply with the rules relating to the appropriate register, as the case may be. (b) An application under section 1(b) of the Act may be amended to change the application to a different register only after submission of an acceptable amendment to allege use under § 2.76 or statement