Career Help (Joining a different branch)

Is there a way to join the secondary branch of a career after you have completed one branch? My sim reached the top of the entertainer career in the music branch but now I want her to reach the top of the entertainer comedy branch. I tried signing her up but the entertainer career is gone on the job list and musician is there. I also just tried cheating her to demote to before the choice but that just caused her to get fired and then you have to wait to rejoin the music career.

I have no mods or cc.