If you have positioned the sketch externelly you can move it in the sketch plane with "Edit Positioning..." (right click the sketch in part navigator)
If you have positioned your sketch in the sketcher, say against datums you will get p-values that you can alter the sketch position in the sketch plane outside the sketcher through Tools->Expression
If you want to totally reposition it you will have to enter the sketch and choose Tools->Reattach and then choose new sketch plane and orientation references. Be aware of the time stamp order, you can´t attach the sketch against datums created after the sketch (but ofcourse you can reorder them before you reattach the sketch)
Or if you simply want to move the curves within a sketch you could use drag. The result of course would depend on what constaints u have in the sketch.
