I want to change a user URL. Any dangers with this?

I have a new user site and the user wants to change the subdomain name. It looks like I (super admin) can change it in the settings for that site.

Is there any danger in changing that as far as accessing the site, which was created by the New Blog Templates plugin? I am also using Prosites, so I want to retain the Paypal payment information so there is not disconnect with the monthly payment.

Just wanted to check on this before I did something stupid and had to ask him to sign up all over again.

It looks simple enough, right?

Thanks, Joe.