Microsoft announced the General Availability of Microsoft Azure Instance Size Flexibility for Azure Reserved Virtual Machine Instances. In the past, when purchasing a Microsoft Reserved Instance, you had to define the size of the virtual machine and the data center. Changing those properties was only possible by using the Exchange function to get a credit for the existing Reserved Instance to use against a new Reserved Instance with the required attributes.
This has changed now and you are no longer prepaying for base compute of a particular virtual machine type, instead you’re now prepaying for a certain amount of compute for a particular family in a specific data center. Now, a Reserved Instance can be applied to any virtual machine in that family, covering all or part of the base compute costs.
For further information on Microsoft Azure Instance Size Flexibility for Azure Reserved Virtual Machine, please visit https://azure.microsoft.com/en-us/blog/general-availability-of-instance-size-flexibility-for-azure-reserved-virtual-machine-instances/ or https://docs.microsoft.com/en-us/azure/virtual-machines/windows/reserved-vm-instance-size-flexibility for some more examples.