The following steps will need to be completed:
First, you will want to setup your Virtual Nameservers. After you
have waited 24-48 hours for your new Nameservers to fully propagate the
Internet, you can start using your new Nameservers. You will only need
to complete this step once.
Second, anytime you sell an account to a friend or client, you will
need to be sure that their domain uses your Nameservers (created in the
step above). Contact the registrar at which your friend or client
originally registered their domain name and ask the registrar to edit
the DNS to use your nameservers.
Afterwards, you will need to wait 24-48 hours for the DNS changes to
fully propagate the Internet. You are done. You can start utilizing the
hosting account for this domain from within your Reseller's Control