To reset OLLY, you will need to first completely remove it from the iPad. To do so, tap and hold on OLLY from the home screen, and your apps should bubble up a bit and have an x button in the top left of their icons. Tap the x button for OLLY and it will ask if you want to delete, press ok and that is that (you can press the home button to go to the normal home screen mode). Once you have done that, go to the App Store and re-download from there.
Hope that helps