Apology Letter For Waking Someone
Dear {Recipient},
My apologies for waking you {in the middle of the night/early in the morning/from your nap/etc.}. You're right, {my question/the discussion/etc.} could've waited. I should've been more patient and considerate.
I hope you were able to get back to sleep without any problem. I promise not to wake you again unless it's really important.
Best,
{Your Name}