N.H. Rev. Stat. § 356-B:25
No condominium shall be expanded except in accordance with the provisions of the declaration and of this chapter. Any such expansion shall be deemed to have occurred at the time of the recordation of site plans and floor plans pursuant to RSA 356-B:20, III, together with an amendment to the declaration, duly executed by the declarant, including, without limitation, all of the owners and lessees of the additional land added to the condominium. Such amendment shall contain a legal description by metes and bounds of the land added to the condominium, and shall reallocate undivided interests in the common areas in accordance with RSA 356-B:18, II. A merger of 2 condominiums the land of which abuts and which is merged by consent of all existing unit owners shall not be considered an "expansion".
RSA 356-B:25
1977, 468:1, eff. Sept. 10, 1977.