fake field goal

[KBoy]

I am not a football official, but officiate other sports and routinely read all forums here.

I have a question about fake field goal and extra point tries under NFHS rules.

1. Ball is snapped accurately to holder whose knee is on the ground as he catches the ball. Can he now legally get up and advance the ball or must his knee be off the ground before receiving the ball from the center.

2. Does this change on a muffed snap; and if the snap is short hopped to the holder can he still get up and advance the ball.

Thanks