Changing primary email associated with a gamertag?

Hello Pam J how are you?
My name is Ezequiel I'm an Independent Consultant. Yes is possible, I'm giving you a method so you can change your email and gamertag, I'm also sending you the official Xbox links to help you. Sign in to your account by using your existing alias and password.
Sign in to your account
Go to Your info at the top of the page.
Select Manage how you sign in to Microsoft.
You might be asked to verify your account before any changes can be made. Follow the instructions that are provided to select your alias:
Select Add email. You can create either a new Outlook.com email address or add an address that you already have. Then, select Add alias. After you’re returned to the previous screen, select Verify, and then follow the instructions that are provided.
Or, select Add phone number. Enter the phone number that you want to use, and then select Next. When you add a new phone number, we'll send a text message to that number to verify it. Enter the code in the text message, and then select Next.

https://support.xbox.com/en-GB/help...nt/change-email-sign-in-for-microsoft-account

To change your gamertag you can do it on your console, press the Xbox button  to open the guide, and then go to Profile & system.
Select your Xbox profile (or select Choose a profile and sign in to your account).
Select My profile > Customiseprofile, and then select your current gamertag.
Under Choose your new gamertag, enter the gamertag that you want in the available text box, and then select Check availability. You may receive a message that says your desired gamertag is unavailable. If so, try again until one is accepted.
On the next page, review how the gamertag will look across Xbox services.
If you're satisfied with your new gamertag, select Change gamertag.

https://support.xbox.com/en-GB/help/account-profile/profile/change-xbox-live-gamertag

You can't delete the gamertag without deleting the entire account. Your best bet is to change the gamertag itself or the the primary email associated with the account.

You could try changing the primary email account with the Gamertag. You will need to set him up an email of his own and then change the email address associated with the Xbox Live account. This should release your email from his gamertag, you may need
to change the family settings first.

Hi Lion,

In order to change out the primary email for a gamertag to another one, the gamertag has to be removed. If there is a gamertag attached to the email, then it will only allow the new email to be connected to the gamertag as a secondary email instead of a
primary email.

Basically, it is going to be like musical chairs. Move each of the gamertags to another email to free the email. Create an account that will not be used on a daily basis. Move the gamertag from the email that is going to be used. Then it will free up the
email to use with the main gamertag.

Follow the steps in this link:
How to change the email address associated with your Microsoft account

I hope this helps ^‿^

You can not really merge to accounts, but you can change the primary email address on the account your gamertag is associated with to the email address of your newer account.

If you still own a Xbox 360 there is a guide available to bind your gamertag to a different live account, which is much more easier to do, then change the primary email address.

support.xbox.com/.../switch-gamertag-to-different-microsoft-account