Do you mean she paws at air when she's in the room and nowhere near you? Or that she paws at you constantly when she's close enough for the paw to reach you?
If you mean she paws at you constantly when she's close enough to reach you, first thing to try is withdrawing. You sit. She paws. You make a uhn uhn noise, get up and leave or at least move from that chair to another. Every time. Stop any petting and make the noise the second a front paw comes off the ground. Needless to say with an established habit, it's going to take doing this a million times to have an effect, and you have to endure. Give yourself a break sometimes by not merely moving away but putting her in a crate, another room, or outside if you have a yard.
If you mean she paws at you constantly when she's close enough to reach you, first thing to try is withdrawing. You sit. She paws. You make a uhn uhn noise, get up and leave or at least move from that chair to another. Every time. Stop any petting and make the noise the second a front paw comes off the ground. Needless to say with an established habit, it's going to take doing this a million times to have an effect, and you have to endure. Give yourself a break sometimes by not merely moving away but putting her in a crate, another room, or outside if you have a yard.