Making Changes to Applications

Hi everyone! I have a couple questions about making changes to applications.

At the beginning of the year, I was hoping to complete an Independent Study in Neuroscience under the mentorship of my old biology teacher. However, due to a scheduling conflict (he needs me to take it 3rd period and there’s no way I can take it then), I am now planning on switching to an IS of French using Rosetta Stone. However, when I filled out the Common App I said that I would be taking Neuroscience. How should I go about alerting my colleges about the schedule change? Would it be best to email them and explain the situation? Or should I call first?

Also, there was a miscommunication between my teacher and counselor about whether or not my English class was AP. Although my counselor originally told me not to designate it as AP on my apps, she’s since changed her mind and has realized that it is indeed an AP class. (Our counseling department is a little disorganized.)

Basically, my question is this: How do I get my applications updated properly and how should I best explain the situations? Will an email suffice?

Thanks in advance for any advice!