It is bit tricky to remove host from maintenance mode and it done using following command.
set-VMHost -vmhost pzesxi-09.pzwaredu.com -State "connected"
set-VMHost -vmhost pzesxi-07.pzwaredu.com -State "connected"
And to set the host in maintenance mode is quite easy
set-VMHost -vmhost pzesxi-09.pzwaredu.com -State "maintenance"