We need a CSR or Private Key to proceed further, if you are moving an SSL cert from a previous server. The Private Key from the previous host is needed.
If this is a new SSL they got from SSL vendor (for the first time for this site) please make sure that they provide us with the following info and we will create a new CSR then you can provide that CSR to your SSL vendor and get the SSL cert. re-issued for your site
Site Name: (or without www.)