The original conditional "if P, then Q" has P and Q swap places to form the converse. So the converse would be "if Q, then P". We don't negate P, and we don't negate Q either.
Here is the full list
Original = If P, then Q
Converse = If Q, then P
Inverse = If not P, then not Q
Contrapositive = If not Q, then not P
Side notes:
The original and contrapositive are equivalent in truth value.
The converse and inverse are equivalent in truth value.