Ms. Nicholson, there are two possible explanations for what happened. One is the explanation you've provided, which is that you accidentally mis-characterized what occurred and used language that you shouldn't have used because it didn't accurately describe what happened. The other explanation is that Mr. Clark was actually involved in the process, did give the green light, tried his best to avoid having any documentation of that, and yet, despite trying to avoid documentation, ended up with this email on June 17, which was then corrected.
For a member of the public who's watching this testimony and trying to decide which of those explanations is the most likely, you'll have to forgive people who think the most likely explanation is the simplest one, which is that the language used in the June 17 email about giving the green light and having been “instrumental” was an accurate reflection of his role in the process.
How do you explain that to reasonable people who are watching this testimony and thinking that it seems like, maybe, something occurred that shouldn't have occurred?