Backup Exec License

Dear Experts,

I have a question regarding license transfer from company 'A' to 'B'.

We have sold the licenses to company 'A'  and now the company 'A' handover these licenses to the 'B'

Yet we haven't registered these licenses to the Backup Exec and we have installed a trial version of Backup exec.

So please assist me with the steps to how we can achieve this?