** Shares of Elixir Energy EXR.AX rise as much as 35% to A$0.027, their highest level since March 27
** The gas explorer says CEO Neil Young retired
** Co appoints Stuart Nicholls as new CEO
** EXR says management changes to help in developing Grandis project, Queensland
** Stock down over 50% this year, including the day's move
(Reporting by Rajasik Mukherjee in Bengaluru)
((Rajasik.Mukherjee@thomsonreuters.com))