Specify is the best I can think of, but it doesn’t by itself capture the change from ambiguity to less ambiguity.
For example:
"I spent my entire net worth to ride a ship", said Blake.
"Since when did boats become so expensive?"
Blake realized that he had been misunderstood, so he specified his statement. "It wasn't a boat. It was a rocketship that I paid exorbitant amounts of money to ride."
I’ve tried searching for synonyms of specify and clarify, but none of them does the trick.
A compound word or phrase would be acceptable.