You can define a custom transposing instrument in the Score Manager's "Instrument" tab. You would then transpose the notes in the full score, but if the transposition has been configured correctly, you can show the Part (via the Document menu) of the transposed instrument where  the notes are as they were in the original and have the pitch play at the transposed pitch.

I'm not sure if I understand your question. If you simply want to HEAR the notes at a different pitch without moving them, you can use an expression, Playback effect set to Type -> Transposition -> Number of half steps, positive or negative.