You can give a users the rights to do certain tasks that they would not ordinarily have the right to do based on their group membership.
This can be applied at the Domain or OU level.
In the example I am about to do it give GoldCoastUser1 the right to change passwords in the Gold Coast OU
Click add and add the user you want to delegate control to.
Here you have the choice of delegating common preset tasks or creating a custom task to delegate.
Click finish and that is all there is to do for a preset task like changing passwords.