My web server has a primary domain plus an addon domain.

I don't use the primary name much but the addon is used

I wasn't going to renew the primary domain name but I have renewed the secondary domain. So I asked the host if this would create problems.

Their reply is
"Converting add-on domain to the main domain will
> cause all other add-on domains and subdomains not to
> function correctly. The procedure that will be
> followed will be to remove the current add-on domain
> ( after taking backup ) and then changing the main
> account name to the add-on domain name, then empty
> the public_html folder contents and then copy the
> files from the backup to the current public_html.
> Please note that any changes that might be needed in
> the code will have to be carried out by yourself as
> we do not provide any coding support. Please let us
> know if you wish to go ahead with the same. We would
> also prefer you to take a complete backup of your
> current site(s) in case."

So is there an easy way to do it or do I start totally scratch all over again.
or keep the old domain.