Dropped AP Calc - who to notify for sched change?

I’m a high school senior and after getting a C first term and D second term in AP Calc, my teacher and I decided I should drop the class. Math just doesn’t come to me naturally and the class was giving me so much stress. So I enrolled in Honors Pre-Calc (for the second time to gain a better grade - junior year I earned a C).

The teacher for pre-calc was fine until I actually came to school after break, and she was insistent on me taking a dual credit class - College Algebra at the local college (This path is generally for people who intend on attending college in-state (South Dakota) and I know that credit wouldn’t transfer to all the east-coast colleges I applied to.) - because she thought retaking the class would be “redundant” and she didn’t want me to “waste my time”.

So, a second change occurred in my schedule. I enrolled in Calc I as a dual credit at the college after speaking with the professor. This path would be much better for me considering I have learned 60% of what the class will be learning and I will hopefully do better in this class.

However, I applied to 5 colleges where I explained my planned transition from AP Calc to H Pre-Calc. For the other 4 I applied to, I had time to change it so I explained changing from AP Calc to DC Calc I.

Who should I contact to notify my schedule change? Is it the regional admissions counselor or the general admissions office for colleges?

***Here is my schedule for this year for a better image. We have block scheduling so there are typically only 4 classes a day.
1st semester
AP Bio
AP Calc
DC Intro to Philosophy
DC French 201 (online)
Independent Study in Painting

2nd semester
AP Bio
Honors US Lit/Comp
DC French 202 (online)
DC Calc I
4th term - outdoor rec (last required gym credit)

(My school only offers 7 AP classes and I have already done AP Lang, Lit, Euro, and US Hist.)