The answers to the clues below will differ by a single letter (ignore a/an):

1. Wait for a master.
2. Make a holy place smaller.
3. Alter an opportunity.
4. Notice a payoff.
5. Enrage a young girl.
6. A flexible reserve
7. Stodgy English landowner
8. Toxic lock-up brew

Answers:

1. Expect an expert.
2. Shrink a shrine.
3. Change a chance.
4. Regard a reward.
5. Madden a maiden.
6. Supple supply
7. Square squire
8. Prison poison

Credit: NPR Weekend Edition Sunday Puzzle
May 28, 2006
Will Shortz (adapted)