You can change it through the meta phone app. So goto the app menu and select "settings" and then "account settings". It eventually takes you to accountscenter.meta.com, so you can probably do it directly from there as well, but I got to it from the phone app.
thanks, but I just realised that i no longer have access to my old email. is there any way for me to factory reset my oculus, then set it up with a new account, without losing some of my games?? if you can help me then THANK YOU because i am running out of hope.