However soon afterwards they realised that they could not do a bunch of things that needed Exchange Enterprise features such as deploy more than 5 Databases.
To recap – The Exchange product key determines the functionality provided by Exchange – the binaries are the same, however the feature set changes.
There's not need to sacrifice chickens, or as the title suggests- call the night nurse at this point, an easy fix is at hand – relicense Exchange.
http://technet.microsoft.com/en-us/library/bb124582.aspx details some of the POST installation steps, including how to license Exchange.
Re-licensing Exchange is as easy as repeating the licensing exercise either in the GUI or in the shell, however this time using the correct Exchange Server keys.
No need for hospitals, or harming innocent fowls 😛
After Entering the correct key, restart the Information Store service and you should be on your way again.