The Swap Letter Puzzle

Many words are just "one letter" apart; that is, it is often true that we can change one word into another by swapping a single letter. Thus fish easily becomes a dish, while diet becomes dint (or dirt or dies, for that matter). Usually, if you're given a single word, it's easy to think of some of the words that could be made by changing a single letter.

For longer words, it's a little harder. Occasionally, I run across a pair of words (or phrases!) related in this way, and I'm wondering if you can guess them.

1. an outrageous film star and an Olympic event?
2. awful and a secluded spot?
3. a fundamental transformation and an expensive operation?

I give up, let me see the solution.