The IHM is to explore ways of working more closely with the NHS Confederation after conceding that the bigger organisation had proved more influential.
At its annual general meeting, a motion calling for the IHM to 'explore practical ways' of closer collaboration was carried.
But delegates asked for reassurance that the IHM would retain its independence - echoing fears raised at the time of the confederation's launch that a body representing employers could not also represent individual managers.
The issue was raised after proposer Keith Clough suggested the IHM could 'become the people division of a combined group', supporting individual members and offering continuing professional development.
The move would offer economies of scale and 'reduce confusion in the media' which did not seem to understand the difference between management and managers, he said.
IHM chief executive Stuart Marples said the resolution was 'positive and supportable'. He had met confederation chief executive Stephen Thornton and the two organisations were working on a shared agenda 'to improve and develop NHS leadership'.
Former institute president and retired NHS regional general manager Bob Nicholls called for reassurance that 'a distinct voice for managers' would be maintained.
Mr Marples said the two organisations had 'different but complementary' remits. In his report, he had acknowledged that the IHM had been disappointed not to have been more closely involved in producing the NHS plan.
He acknowledged the confederation's role in the process. 'There are many things in the plan, like the leadership centre, which would not be there without the confederation, 'he said.
'We don't yet have a place on the modernisation board, he concluded, adding: . The IHM will have to 'work through our members on that board and other organisations'.
Unaudited accounts were agreed by the AGM and members were informed that Val Hempsey, a practice manager from Gateshead, had been elected unopposed as IHM vice-chair.