-- In "how do you do" relex doesn't interpret "how" at all.
-- In "how are you" relex interprets "how" as a predicate rather than a q-word
-- In predicative "how" questions, such as "How was your dinner?" it works for past tense sentences, but not for present tense ("How is your dinner?"); for present tense sentences it outputs no query-flag nor %copula relation (which it uses for the past tense versions).