OK then.  You must be using soundpool objects (samples).  It would have been helpful to tell us that from the start.

You can change the "key" of a soundpool object by selecting one of the numbered bars at the top of the media pool.

For a melodic object, you can select seven different variations in pitch.  For rhythmic objects, you may have the option of seven different rhythm patterns.

The only other option is to pitch shift the object from the Object Effects Rack.

If you wish to change keys from major to minor, for example, you will have to create your own MIDI objects using the Vita MIDI Editor.