Hello there, HK55.
The following Knowledge Base article offers up some great follow-up information for once you've changed your Apple ID:
Apple ID: What to do after you change your Apple ID
http://support.apple.com/kb/HT5796
For iCloud on an iOS device it recommends the following:
iOS 6 and later: Go to Settings > iCloud.
- If you signed out before changing your Apple ID, enter your current Apple ID to sign in. The data from your iCloud account will download to your device.
- If you're still signed in with your previous Apple ID:
- Scroll down and tap Delete Account. Depending on what iCloud options are turned on, you'll be asked to confirm that you want to delete data from your device. To confirm, tap Delete. (If you're using iOS 7 and have Find My iPhone turned on, you'll be asked to enter the password for your previous Apple ID. Enter the password, then tap Turn Off.) The data will be deleted from your device, but not from iCloud.
- Enter your current Apple ID to sign in. The data from your iCloud account will download again to your device.
Thanks for reaching out to Apple Support Communities.
Cheers,
Pedro.