In Dragon Ball Super, we have seen Trunks traveling across timeline using a time machine and even Zamasu or Gowasu using a time ring. And unlike Gowasu, Zamasu/Trunks have changed events, and this has been depicted as a bad and forbidden thing.
We have also Whis reversing time ("Temporal Do-Over") in the Resurrection F saga and he has even explained that he can reverse time by 3 minutes in case of emergencies.
My questions are:
- What is the difference between Time travel and Temporal Do-Over?
- Why are angels allowed to change timelines but it's forbidden for even Gods?