I think the best way is probably select the clip then use the
Process->Transpose... dialog. (Edit - I changed my mind. Is this really better than the groove clip method?!!!)
In that dialog you give the number of half-steps. Then check the
Transpose Audio box. Then choose the type of calculation. My first guess is
Radius Mix-Advanced will be the best. Two sliders then become enabled. I'd try raising the pitch slider. Or you can try
MPEX - mix, polyphonic and fool with formant scaling. Either way, prepare to be disappointed if you are transposing vocals very far.
It takes a long time (uses a single CPU), so if you are just experimenting to find the best settings, do it on a short section.