Which two items are required when a VM-100 BYOL instance is upgraded to a VM-300...

In a public cloud deployment, if your firewall is licensed with the BYOL option, you must Deactivate VM before you change the instance type or VM type and apply the license again on the firewall after you complete the model or instance upgrade. When you change the instance type, because the firewall has a new UUID and CPU ID, the existing license will no longer be valid.

https://docs.paloaltonetworks.com/vm-series/9-0/vm-series-deployment/about-the-vm-series-firewall/upgrade-the-vm-series-firewall/upgrade-the-vm-series-model