Architecture practice Aedas has separated its UK and European business from its Hong Kong and US divisions.
Eight UK locations, including the 80-strong Manchester office, as well as offices in Russia, Poland and Kazakhstan will operate from now on as AHR.
The 13 offices in China, South-East Asia, the Middle East and the US, will continue under the Aedas brand.
Aedas was formed in 2002 from a merger between AHR, formerly Abbey Holford Rowe, and Asia-based LPT.
Aedas said the demerger would allow both companies to focus on their respective strengths and will enable them to grow the businesses in different directions. The intention is that both groups will continue to work together on projects in the future.
Keith Griffiths, chairman of Aedas, said: "This move reinforces Aedas primary aim to provide international design services to the major world cities through our network of 13 offices and 1400 staff."
Brian Johnson, chairman of AHR, said: "We believe that this is a very natural evolution based on how the practice has been operating in recent years and to all intents and purposes there will be no change for our clients or our 450 staff."
Recent appointments for Aedas in the North West include Realty Estates' Oxford Road site, work at Muse Developments' Talbot Gateway in Blackpool and the development of Altrincham's new £13m General Hospital. These projects will now be undertaken by AHR.
AHR will remain in Aedas' previous office in Parsonage Chambers in Manchester.