I'm going to change my name and leave in the middle of the night without telling anyone
Why are you going to run away and change your name?
I don't want anyone to know who I am or where I'm going.
Disappearing without telling any of your friends or family is not a good thing to do. They'll be worried about you and might think that something terrible has happened. If you want to leave you should at least let them know that you're safe.
Are you telling me that I can't leave?
No, if you are an adult, you have every right to leave and go where you please. However, think of how upset your family and friends will be if you suddenly vanish from their lives without any explanation. For the rest of their lives they will wonder what happened to you.