Changing my email address to another one.

Shouldn't be an issue. You'll need to create a dummy email address in order to free up the other account. Simply follow the instructions at this link to change the address.

support.xbox.com/.../microsoft-account-faq

Thank you is it possible to change the email address associated with the account? For example- the account is with my email address. Could i change it to my childs email address? Then create another account with my email address and add his account
to the family?

Hello, what you would need to do is change the email address associated with the GT you want to use. So if the email address you want to use is tied to another GT you'd also need to move that GT to another email address to free up the one you want to use.
The following link will assist you in the process of changing email addresses associated with accounts.

http://support.xbox.com/en-US/my-ac...nt/change-email-sign-in-for-microsoft-account

I'm trying to add my new email as alias on my old gamertag but it doesn't work!

I select "Add an existing email address as a Microsoft account alias" and than I put my email @outlook.com when a message comes up "This email address is already taken. Please try another one"

Is there another way to change the email associated to my old gamertag? Thanks

You can't transfer anything from one account to another. You can change the email account on the account off your hotmail email address to his own personal email address. https://support.xbox.com/en-US/my-a...nt/change-email-sign-in-for-microsoft-account