more characters for gamertags

Is what you're trying to use for the second one already taken? And are you doing it on PC or Console? Because on PC, it gives me

no such issue.

You technically still have the 15 character limit. The gamertag that appears on the system and apps is 12 characters, yes, but you're able to change your gamertag for games not supporting the new gamertag change. You should see

a prompt to customize your gamertag. The one you're changing when selecting said prompt will be the gamertag that appears in games and can go up to 15 characters.

I'm trying to change my gamertag that is as equally long as the one I have. When I go to profile and click on my gamertag then insert the new 15 characters it notifies me that I could not

yes I am having problem with changing my gamertag and it says your gamertag needs to be 12 characters or less could you guys fix it to more characters I am trying to get a new gamertag like to 24 characters the gamertag that I am trying to get 16 characters
and including spaces

I don't understand. My gamertag with my old xbox live account have more characters than 12 characters.