to make convert from one to another as twisted curve - I mean the coordinates , you need before use rational number in sage math.
then you can easly use P.reduced(new_prime)
If will be one example code how to convert I will do all necessary.
looks like for get poont with priv 1 what you thant need try cicle from 1 to and of a p, and take small p and see what is going on.Because oy random find a valid point on iso curve....