The dog training levels should be replayable each day while the event is active.
I completed the dog training levels getting 8 hrs of unlimited lives, but was only able to use an hour and a half because real life happens. Meaning I lost 6 and half hours of my reward. I would like to be able to complete the event again today as I have more time to play the game, but once you complete it it goes away. It should reset every day giving us a chance to complete the event again.