How can I substitute a pc in my multiple-license subscription ?

For several weeks I was waiting for an answer from Avast Support: I changed one of my PCs and I need to substitute it to another in my multiple license. How can I do ?
I paid for a 3-package PCs licence and I have one of them without that.
Can anyone help me to substitute a PC in my multiple license ?
Thanks in advance.

  1. Uninstall on old machine.
  2. Reinstall on new machine.
  3. Enter license. Done.