Failing a Quest and attempting it again

Hi Martin

If I choose to fail a quest (because I need to heal and re-supply) -

a) Can I keep the same dungeon sheet and just continue, or do I need to start a new sheet. I reasoned that I'm going back to the same dungeon.

b) If I can keep the old dungeon then do I still have to erase the levers and keys? (again, I ruled no, because it was still the same dungeon.)

Thanks