In database view we are able to convert a one-time gift to recurring. That will not be an option in NXT (see article link below). In chatting with support to try and convert a donation that had not yet been approved I was told it wasn't a but that it was working as designed. Now I have to tell the donor that I can't convert and they need to re-enter their donation.

https://community.blackbaud.com/categories/blackbaud-raiser-s-edge-nxt-ideas