If this is against your existing system, you would need to run the upgrade request through ECN and then order through a distributor (like Westcon). They would then process with Avaya and issue a new keycode file for you to install in your system.
If you have a maintenance provider you should be able to have them run this for you.
To order any type of expansion on the system, the company placing the order has to be Product Authorized on the CS1000 to place the order or the Distributor cannot order from Avaya.
if they do electronic, they would just set your new license in KRS and your vendor of record can pull the new keycode file from KRS.