N.J. Stat. § 17:12B-28
A State association may change the location of its principal office to a location then occupied by a branch office operated by it, subject to the requirements herein set forth:
The State association may, in such case, operate its principal office at the location previously occupied by its branch office and may operate a branch office at the location previously occupied by its principal office without further requirement.
The failure of a State association to complete such interchange within 12 months after filing the certificate or after approval by the commissioner, as the case may be, shall automatically terminate the rights of the State association to effect such interchange, except that, for good cause shown, the commissioner may in his discretion on application of the State association, extend for additional periods, not in excess of 12 months each, the time within which such interchange may be effected, provided the initial application shall be made before the expiration of 12 months from the date that the commissioner approves the application and any subsequent application for extension shall be made before the expiration of any subsequent period for which permission to extend is granted by the commissioner.
N.J.S. § 17:12B-28