First job - find someone who wants to do it - your quest may end there unfortunatley.
Second - Find out if they are any better than what we already have.
Third - New administrator needs to secure the majority of votes at the AGM.
Fourth - New people take over after a messy hand over from the now very p1ssed off ex administrator who keeps as much cash and information as possible.
It may be possible but not easy given the number of voters at an AGM - unfortunatley 30% don't pay so can't vote, 30% don't care anyway, 20% don't know how to or forget or just can't be bothered, 20% actually make the effort of which half of those may still be in the hands of the developer meaning they get approx 50% of the overall vote. Now bear in mind it was the developer that put them there in the first place and with other developments around the corner...........................................................................
Figures may not be exact but doubt I am far wrong - shame but it won't be easy but good luck as you'll get my vote.