change pitch mutiple times in an audio

Sorry, it's just really difficult for me to explain, because I don't know what it is called.

I have a song I put into Garageband. To create a weird effect (I am using the song in a theatre play) I would like to use pitch shifter and change the pitch up and down several times, so you can hear the pitch change. I have found pitch shifter in the program and I can change the pitch while the song is playing. Now my question is how to record that so I don't have to sit and do it manually every time.

Yes, that is what I mean. The problem though is that the song is already a finished song and I only want the program to record the pitch being changed while the song i playing.

I have done it in Cubase some years ago and I am sure it is possible! I just do not know how

Yes, that is what I mean. The problem though is that the song is already a finished song and I only want the program to record the pitch being changed while the song i playing.

I have done it in Cubase some years ago and I am sure it is possible! I just do not know how

Thank you so much!!