On Saturday, February 4, 2017 at 8:18:00 PM UTC-8, Del Jensen wrote:
Many thanks Dan. I was little bit concerned over whether I could take the glider somewhere on an occasional basis (e.g., Parowan). You've set my mind at ease.

Del

I am pretty sure a program letter won't override any limitations in the airworthiness certificate. You need a new airworthiness certificate. But I could be wrong . . .