How can assign a premium plan to different site in my Wix account?
To assign your premium plan to another Wix site: Sign in to your Wix account > hover over Subscriptions > click Premium Plans > under the relevant plan, click Transfer > select the new site > click OK.
Make sure to assign your domain to your updated site. After transferring your plan, under Manage Premium, click Domains > next to the relevant domain, click Manage.
Under Domain Connects To, click Change > select the relevant site > click Save.