This method used to be used for Banned Tags.
Ring MS make a Bullshit Story and they'll swap your Tags.
This is just the method of the unbanned version.
METHOD FOR BANNED TAGS!
Salvaging your account.
You need the OG email of the Tag you want Unbanned.
You need a new email of a unchanged Gamertag (one that MS gives you)
Next step is to create a Dummy email. Make a windows lifve ID (Do not register this with Xbox)
just give it credentials via passport.net.
So thats a total of 2 GT Emails and One "Dummy" email.
Once your dummy email has been created for 30 days
you log onto new account(the silver from LIVE) go to account security.
after that click on "change microsoft account" then you would put dummy email information so it can update it.
after that you would call xbox support and tell them that you have the
"change microsoft account" ready so they can lift the ban and link it to new account.
The rest of the Method is only for you to do. Good luck.
MAKE SURE TO GIVE THEM FAKE STORY. But make it Good.

(A fake story about your Tag being banned so they can Swap your Tag onto a fresh account)
WARNING: MS will not unban accounts using this method. This method is proved to Swap Banned Tags (Not Accounts).
XBL Gold membership can not be touched if it still has membership. No DLC or GOD can be added to your New account. Only the GamerTag! Enjoy!
Good Luck Se'ing your banned Tag.