Letters of Recommendation for Common App

Alright so here’s the problem, I am applying to a few colleges who require a English and Math teacher letter of rec. Some of these schools need only a math core subject teacher but other allow a Computer Science teacher. I would prefer my CS teacher write the letters of rec when he can but some of my requests have already been sent out to my math teacher.

I know that you can reuse the letters of rec on the common app for different schools. But I was wondering if there was a way to switch out the recommender after requesting the letter of rec while still saving the letter for other schools.

Thanks in advance!