N.H. Rev. Stat. § 360:21
A personal property mortgage may provide that the mortgagor with the permission of the mortgagee may sell or exchange any of the mortgaged property in accordance with the provisions of the mortgage without notice to or consent of any subsequent mortgagee or lienor of the mortgaged property, if the proceeds of such sale or exchange are applied upon the mortgage debt or are used for the purchase of property to be included in the mortgage lien, or are used for the purpose of paying the expense of cultivating, harvesting, preparing for market, processing, marketing, or otherwise preserving or rendering marketable or salable the remaining property covered by the mortgage, and no such provision shall in any way render invalid or affect the lien of the mortgagor or its preference or priority; but unless the mortgage so permits, no mortgagor shall sell, pledge, or exchange any of the mortgaged property without the written consent of the mortgagee, recorded in the office where the mortgage is recorded, or endorsed upon the mortgage and upon the margin of the record thereof.
RSA 360:21
RS 132:8. CS 138:11. GS 123:13. GL 137:13. PS 140:13. PL 216 :17. 1935, 41:4. RL 262:19.