Apple ID name change

I have an Apple ID that I have used for most applications. The ID is my first name initial and last name (for example jsmith). When I bought an iPad, I needed an ID with my email address for "Find my iPad", so I used my Google address (for example jsmith@gmail.com). I would like to change my old Apple ID (jsmith) to the one with the email address. Apple won't let me do this because the new ID is in use. Can I change the new ID to another email, and then change the old ID to the current email (jsmith@gmail.com)?