"Specify" is the best I can think of, but it doesn't by itself capture the change from ambiguity to less ambiguity.

Ex: "He then specified his statement: 'There will be no water involved. It's a *rocket*ship that I paid exorbitant amounts of money to ride.'. Does this make sense grammatically? Assume I can't remove the words, "his statement".

I've tried searching for synonyms of "specify" and "clarify", but none of them do the trick.

A compound word or phrase would be acceptable.