How to upgrade from Pro to Pro PLus?

I have a 1-yr license for CCleaner Pro, but I would now like to install the software on an additional computer. I understand that a Pro Plus license would allow this at a reduced price than two separate Pro licenses, but I can find an easy way to upgrade my current license. Please advice. Thanks.

It would probably be better to contact Piriform direct for info about this.

Either here

https://support.piriform.com/hc/en-us/requests/new

or by email

support@ccleaner.com

Thank you!