remove license from one computer and apply credit to other?

I had 2 computers on my account, but have sold one of them. Can I take the remaining credit for the one that was sold and apply it to the remaining one? If so, pls tell me exactly how to do this.
Thanks!

No, you can’t.

Whilst there isn’t an easy way to do this, it may be possible manually, but there is no guarantee that it can be done

You could try contacting sales via the support ticket system:
https://support.avast.com/Tickets/Submit/RenderForm/27/&cls02&ptf01&lic01&scr06
Choose your language and submit your problem directly to Avast and see if they can’t merge both and send you a modified license.

This is like selling your car, buying a new one and than ask “Say, I still have fuel in my old car. Can you put it in my new one?” ;D

B.T.W. https://www.avast.com/find-order
Make sure auto-renewal is disabled for the license you used on that system.
If not, the license will be renewed and you will have to pay for it.

Nothing like it at all, considering that avast already have a license modification option for it in the support ticket system (previously attached image).