N.H. Rev. Stat. § 109:11
If, while any fire-fighting personnel or equipment pertaining to a New Hampshire municipality is engaged in rendering emergency fire assistance upon call in another municipality within the state, a fire emergency develops within the municipality to which the assisting fire-fighting personnel and equipment pertain, the chief executive officer of such municipality shall determine whether such personnel and equipment shall be recalled in order to meet the local fire emergency. Upon the recall order issued by such chief executive officer of the assisting municipality, the personnel and equipment shall forthwith return to their normal stations or to the place specified in such recall order. The decision of the chief executive officer of the assisting municipality, made under the emergency conditions contemplated by this chapter, shall supersede any agreements or arrangements for mutual assistance entered into as provided in RSA 109:3.
RSA 109:11
1949, 257:1, par. 11, eff. June 16, 1949.