It is the first major move by David Patton since joining as Y&R’s global president this month.
The rebrand follows a tumultuous two years for the agency, which has lost several key accounts including Marks & Spencer and Premier Inn last year, as well as Lloyds Bank, Vodafone and Land Rover in 2015.
Jon Sharpe, who was named chief executive at the end of 2015, hired Jonathan Burley from CHI & Partners as chief creative officer and promoted Emily James to chief strategy officer in 2016.
Sharpe said the agency is increasingly a hub for pan-European and global relationships, pointing to global account wins last year including the Premier League and Chanel. He added that becoming Y&R London is the "natural response" to this demand.
Y&R acquired RKCR for £25m in 1999, six years after it launched. Mark Roalfe, the only founder still at the shop, will remain chairman.