Thomas joins the company from New Zealand agency Clemenger BBDO Direct where he was creative director.
Warner transferred from the Rapp Collins New York office where he was a group creative director on the Mercedes-Benz, Discovery Channel, Gardasil and XM Satellite accounts.
Former creative director Cockerell and digital director Haslam became joint executive creative directors. Platt takes the same role at Rapp Collins Los Angeles.
The re-shuffle was instigated by the agency’s chairman, Ian Haworth, who is also global chief creative officer of the Rapp Collins network.
“These promotions and hirings signal our determination to continually evolve our creative offering, broaden our skills base and work with the very best creative talent in the business,” he said.