Is it possible to setup wildcard subdomain for an existing WordPress multisite?

Hi,

I'm moving wordpress installations from my current host to a new one. I'm gonna move over the whole cpanel and then delete unnecessary wordpress installations. The one I try to keep is installed on an addon domain. its not the primary domain in use. Since, this is a Wordpress multisite, I want to setup wild card sub domain. I heard its not possible to setup wild card sub domain for a site that's not created in the root directory (the one I try to keep is on an add on domain folder). So, I got two questions that I seek answers,

1. Is it possible to move the Wordpress multisite I try to keep to the root directory and use that domain as the primary one?

2. Is it possible to setup wildcard sub domain for an existing WordPress multisite installation? is it necessary to have a fresh Wordpress installation in order for wild card sub domain to work?

Appreciate any help!
Thanks.