Test AD Takeover

Hi all,

I have a question, and hope someone could shed some light on a topic. I have a client with an existing AD domain, with approximately 200 users. They would like to see how they could manage with UCS.

They want the existing AD to remain functional, but in the mean time would like to test UCS also, with the same accounts and settings in parallel with the AD. If they like it, we would switch completely to UCS, but if they don’t the existing AD will remain.

How can i proceed in this situation? I thought of the following:
Takeover: I don’t know if the existing AD will remain functional after the takeover, and can both of them run simultaneously?
Join AD: I could join UCS to the existing AD, but then, if they switch to UCS i don’t know how to promote UCS to master domain controller, and switch the existing AD completely off.

Thanks in advance,