Subdomain is a branch of domain name that is used to add separate contents. When subdomain is wrongly configured or you would like to change the domain name according to your likelihood. You can change the following way.
Changing Subdomain name is not possible so far but pointing new domain name to old folder can be done easily.
This progress will delete the old subdomain but not underlying folder under it.
Go to Domain Section and Choose Subdomain or if you are currently subdomain page. Press Create new Subdomain.
Don’t forget to update your dns to redirect back to New subdomain otherwise they will see the server default page.