Use DISM to change your 2012r2 Standard Evaluation to Non-Evaluation

Did your test environment turn into prod again? If so, here are the steps to change a 2012r2 Standard Evaluation License into a 2012r2 Standard License. The 2012r2 Standard license used below is for Automatic Virtual Machine Activation (AVMA). So unless you're running a 2012r2 Datacenter Hyper-V as your HyperVisor you'll need to go get a key. 

dism /online /get-currentedition

dism /online /get-currentedition

dism /online /set-edition:ServerStandard /ProductKey:AVMAKey /AcceptEula

dism /online /set-edition:ServerStandard /ProductKey:AVMAKey /AcceptEula