Frazer was deputy chairman of Grass Roots' meetings, events and communications division when he left on 31 December.
Prior to that role, he was Maritz-Europa's vice president.
A statement from the agency said Frazer "plans to continue working but at a less frantic pace".
Announcing his departure to staff, Frazer said: "I have enjoyed a thoroughly interesting career and the highlights for me have been arranging many of the largest global and European product launches and training events for up to 16,000 delegates, as well as some of the most extraordinary incentive programmes ever created. These events have been not only exciting and extremely challenging, but they put us in a completely different league from most of our European competitors."
Grass Roots head of global events Nick Bender said: "Graham has many friends here at Grass Roots and in our industry and all of us wish him well for the future."