Keep my apple ID (gmail address)... CHANGE new icloud address?

I'm only starting a new discussion because everytime someone asks the same question I have, everyone starts providing answers to a DIFFERENT problem.

The backstory:

I have a longstanding apple ID. I like it; it has worked fine. I have an iPhone 4S. I was setting up iCloud on my son's iPhone 4S, when I noticed that "Notes" was an option for syncing with iCloud. I thought: that's nice, I'll turn that on for all of us, so our Notes can be saved to iCloud.

When I turned Notes on, a popup said that you could only sync Notes if you had a required icloud address, and it prompted me to create one. I thought I was creating one for my son. I added his name before the @icloud.com.

When I went to iCloud, it now says my apple ID is both my gmail address AND this icloud address I thought I was just creating for my son. I want it gone, or changed.

Here's what I have tried:

• I went to "Manage my Apple ID" and removed the icloud address. No dice.
• I deleted iCloud from the devices and put it back on. No go.

I would like a simple: yes/no answer:

Is it possible to change ONLY the icloud address associated with my (gmail) apple ID?