Graham Keene is moving from executive chairman to group chairman, while Martin Parry will step up from UK managing director to group chief executive officer.
Keene will continue to be responsible for the overall group vision and the group's recent expansion into the Asian market.
Parry, meanwhile, will be responsible for implementing the group's strategy and delivering the business's bottom-line growth.
Reporting into Parry will be Mark Saxby, who becomes group sales and marketing director, plus group finance director Jeremy Wilson, group operations director Andy Tattersall, European director Andrew Winterburn and US chief executive Gary Dickinson.
Keene said: "World Events is now an established global event agency and we need a management structure that continues to deliver the excellent results of the past five years but equally is able to grow with the business as we develop our international offer further."
Parry added: "I am delighted to have been given the opportunity to lead the profitable development of our core businesses on an international level, despite the challenging nature of the markets we are operating in."