Q: How do I erase and add a new iCloud account?

Hi Sheyandsophie,
 

Thanks for visiting Apple Support Communities.
 

You'll have to enter your password to sign out of iCloud and erase the account from your new phone, according to Sign in with a different Apple ID on your iPhone, iPad, or iPod touch.
 

You can reset your iCloud password using the steps in If you forgot your Apple ID password.
 

Sincerely.