To Update Maintenance Licensing dates:

1 -  From the Start Menu: Right click and Launch PowerOLAP Server Control Program as an Admin

2 - Select Edit > Options to view licensing from within Server Control Program 

*You will need to do steps 1 and 2 for any Designer and/or Scheduler client as well

3 - If license is still not updated in PO Server > stop and start the PowerOLAP Service

4 - Re-check licensing again.