By the standard way of imputing the new key into the activation form, you’ll get an error that this edition could not be upgraded. However, the MS guide stands for if you’d like to activate your Azure configuration server you’d need to do that through DISM:
And the command is simple as that:
DISM.exe /Online /Set-Edition:ServerStandard /AcceptEula /ProductKey:WC2BQ-8NRM3-FDDYY-2BFGV-KHKQY
After the restart, you’ll get the normal windows server standard edition connected to Azure.