Nick is correct. You can warm transfer on both Workplace for Windows and for mobile in a similar way. Add a new party to the call, and the first party goes on hold. Merge the calls together, and when you hang up they will stay on with each other. We all acknowledge it's not as clear how to do it as on a desk phone, but it does work.

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.