how can i change the icloud name

See Change your Apple ID https://support.apple.com/en-us/HT202667. 

And, here is What to do after you change your Apple ID or 

Password https://support.apple.com/en-us/HT204071  (supplementary to what the fist link says)

Post back if you have questions about what you can do if your Apple ID (1) is a third-party apple ID or (2) ends in icloud.com, me.com, or mac.com. 

Try this:

1. Go to appleid.apple.com and sign in.
2. In the Account section, choose Edit.
3. Choose Change Apple ID.
4. Enter the email address that you want to use.
5. Choose Continue.

Are you trying to change an iCloud email address name? You can't remove/change @iCloud.com, @me.com or @mac.com aliases.