Hello,
Apologize as I do not understand the word "upgrade rebate".
What version of SEP are you currently running?
Is the License of the current Symantec Endpoint Protection expired or about to expire?
In case you are using the Symantec Endpoint Protection 11.x and you want to upgrade the License to Symantec Endpoint Protection 12.1.
Check this Article:
How to upgrade your Symantec Endpoint Protection 11 license to Symantec Endpoint Protection 12.1 online
http://www.symantec.com/docs/HOWTO56030
In case of anything else, you can also contact Symantec Sales:
Renewals
To renew or view details of your Symantec support contracts visit our License Renewal Center.
Hope that helps!!