Richards Butler last week voted to merge with US firm Reed Smith to create a £400m transatlantic firm. Reed Smith is kicking off its integration plans immediately, as it transfers its director of strategic planning Michael Pollack from its Pittsburgh HQ to London.
Pollack will take responsibility for integration, together with UK managing partner Tim Foster and European chief Roger Parker, ahead of its January completion.
Reed Smith chairman Greg Jordan said: "Michael's move sends an important message that this is a very serious thing for us."
The firms are now hoping they can convince Richards Butler Hong Kong, which operates as a separate partnership, to sign up to the deal.
Pollack said: "Before we were talking to Richards Butler, we were looking at ways to get into the Chinese market. And if we can't do it with Richards Butler Hong Kong, we'll find another way to do it."