An Azure service that is used to provision Windows and Linux virtual machines.
Why not just migrate all of these resources to ARM? For a single VM this is likely to be a very straightforward process and probably without any downtime for you.
Please review the process below. You can perform the validation without making any changes and it will tell you if the migration is possible or if you have to make any changes first.
https://learn.microsoft.com/en-us/azure/virtual-machines/migration-classic-resource-manager-overview