Cable Forum - Swap live account

Quote:

1
From your Xbox, go to the settings menu and then open up the account menu.

2
From this menu head to "Your information" and open "Account security", and then select "Microsoft account".
Here you will change the Microsoft account associated to your gamertag.

3
When prompted, select "Yes", indicating that you have another Microsoft account.
You will be prompted for the password of the current Microsoft account. Enter this now and select "Sign in".

4
After loading, you are given the option to enter the new Microsoft account that you wish to move the gamertag to.
Enter the email address and the password for this account and then choose "Sign in".

5
When prompted, choose "Yes" to confirm that you want to move your gamertag to the new Microsoft account.

6
On the final screen, you can either update your contact details if they are incorrect or choose "Done" to complete the process.
The change may take a few minutes to reflect across all of your Microsoft devices.

Credit: http://visihow.com/Switch_Your_Xbox_...rosoft_Account

Now this was the 360 method. But I believe the concept is the same on Xbox One, someone with an Xbox One may be able to fill in any gaps or correct the method.