If a recipe calls for Pectin NH can I use other pectin?
No, you can't. 

Different pectins set under different conditions. Some require calcium, others require a high percentage of sugar. All have their own optimal pH range. 

When a recipe is optimised for one type of pectin, other types won't set properly. Normally, you cannot substitute in any direction. 

The linked question from Jolenealaska's comment provides further information.