Part-Combi alto and voice

Out of a big band score I made a combination of the alto 1 part and the voice part. The voicepart displays in concert range and needs to be transposed.
What is the best way to do so? Manually make a new transposed voicepart in the score? I’m sure Dorico has better options than that. Anyone?

Right-click the layout in the right panel of Setup mode and click Clef and Transposition Overrides. Hopefully the dialog is self-explanatory but if not, see Clef and Transposition Overrides dialog

Thanks again, Leo!