Powder pectin and liquid pectin can be substituted for each other. Interchanging the two does change how the food is cooked.
Using either powder or liquid pectin will give the final recipe the same result. There are a few differences when making a substitution. Not as much powdered pectin is needed as compared to liquid. Use only 2 tablespoons of powder when the recipe calls for a package of liquid. Also, do not add the sugar at the beginning when using powder. Bring the powder pectin, juice and fruit to a boil for a minute before adding the sugar to the recipe.