How do I combine all the devices on a single subscription?

I discovered that I have two subscriptions for Norton 360 for Windows.  Each allows up to 5 devices.  I currently have two devices on subscription #1 and two different devices on subscription #2.  How do I combine all the devices on a single subscription?

Norton 360 Deluxe

Windows 10 Home, Version - 21H1, Build - 19043.1288

[Edit: Calrified the subject]

thank you peterweb

You need to contact Norton Support and have merge the two subscriptions, which will combine the time to extend your protection.   www.norton.com/contactcs