Danny -- Workplace actually does support warm transfers, but it's not obvious how to do it. I know we've run into this quite a bit with our users. Essentially, you place the call on hold, place the new call within the Workplace app, then you have the option to do the transfer. It's not like other Avaya apps or physical desk phones.

There is an online tutorial here : https://cdn.avaya-learning.com/CDN_EU/LandingPages/Workplace/user.html (Transferring is under the "Getting Started" section).

I do believe we will be forwarding this on to Avaya -- there should be a more obvious way to do attended transfers -- just like their other products.