The management restructure at Expotel has propelled former non-executive chairman Richard Lovell into the agency’s executive chairman role.
Lovell was previously president EMEA and Latin America for Carlson Wagonlit Travel and joined Expotel in 2008.
Meanwhile, Burnley was appointed as chief executive of Expotel in 2006 and led a management buyout in 2008 with Phoenix Equity Partners.
He also spearheaded four acquisitions including NIS and Venues Event Management.
Burnley told C&IT he was "unable to comment at this stage" but expected to provide an update. He left on 25 May, Lovell told C&IT.
"Ian has enormous strengths in deal-making and buying and selling companies," said Lovell. "We are in a longer term development now with Phoenix behind us in developing our C&I offer overall. This transition will take some time to manage and requires a different skill set."
Lovell added that "part of the discussion at the moment is whether Ian might have some continuing work with us in the future".
However, he said the business is "actively looking to appoint a new CEO as soon as possible".
Venues Event Management chief executive Anita Lowe said there was "nothing untoward" and the business was seeing the restructure in a "positive light".
"Richard Lovell has a lot of industry experience and knowledge," she said. "Ian Burnley has been incredible with us because he brought us into the fold and was our spearhead. We had a strong relationship with Ian because he is the person we negotiated the acquisition with."
Expotel acquired Venues Event Management on 1 November 2010 for an undisclosed sum in a bid to bolster its meetings and events offering, however the businesses have remained distinct with their own identities.
"It may have come as a bit of a surprise to our industry colleagues, but Ian has been incredibly upbeat and proactive in the market place," added Lowe. "The cross opportunities for Expotel and Venues Event Management are very strong. We will be reporting directly into Richard Lovell and looking forward to that."
Lovell said the aim was to evolve the business from a hotel booking agent to a TMC.
"We have exciting plans to consolidate this position by expanding our core offering, as well as to continue to acquire other high quality businesses," he added. "The group remains financially strong and is making excellent headway in a tough market having recently signed over £50m of incremental business across the government and corporate sectors."