Scaleset upgrade from 80.30 to 80.40

[seppoe]

Hello

We have Checkpoint vmss cluster in Azure and we need to upgrade them to version 80.40 from version 80.30, how is that done in proper way? 

Our management is already running 80.40 so no need to upgrade that..

I was thinking so that deleting one node at a time from management and from Azure and creating them again will to the trick as long as the template on management has correct version.