Free up previously used GamerTags?

From a user end, changing a tag will usually free it up for use, but it may not be immediate. Other than that, if a person doesn't sign into their Microsoft Account for 2 years, it will be freed up.

ElfenSky is in use which is why you do receive the suffix.

Hi EmperorElfenSky,

Check out the Microsoft account activity policy. It states that the company have the right to close all “inactive” accounts
if the player does not sign in at least once in a two-year period. After that period has passed, Microsoft will deem the account to be inactive and the gamertag would be available for anyone to grab. However there are excemptions
on the policy page that will stop this from happening.

The above is the only way that a gamertag in use by someone else can be made available again.

if you have previously changed your gamertag then you won't be able to use your one free change, Also if you changed, altered or picked your own gamertag when you first signed up your account then the free change will not apply to you.

Deleting the account won't free up the gamertag or the Microsoft Account addresse used for the account. Microsoft Accounts also imposes a 30 day 'speed bump' delay on creating a new account with a previously used addresse. You can change that addresse on
your console by signing in then going to Settings | Account | -> -> Account Security | Change Microsoft Account if you first create a new Microsoft Account addresse to free up the addresse you want to use on your own gamertag.

As I said previously - Unfortunately the support team will not be able to transfer any data from one account to another. If you wish to use the "name" of your original profile with a new account then changing the gamertag will free that name up
for further use.