>> well, i mean, the answer -- kristen holmes at the white house what have you learned? >> reporter: ana, this letter is the question sort of answers coming a day after bolton did itself. doesn't it? not show up for his deposition there are sometimes vald reaso s from his attorneys to these house committees. i'll read you a part of it and s, to keep advice to a president we'll get to what it means. confidential. in the letter, ambassador bolton as we learned in the clinton investigation and in the nixon national security adviser to the president and personally investigation, that involved in many of the events, confidentiality requirement meetings and conversations about evaporates when what's under which you have already received investigation is quite literally testimony as well as many criminal or impeachable conduct. relevant meetings and conversations that have not yet been discussed in testimony so >> one person who did testify, gordon sondland. his name comes up a lot in the far. obviously a lot of news. the big thing what exactly does testimony seen so far. bolton know? he had to go revise his and what doesn't the house know testimony he earlier gave to that bolton knows here? congress. a very important development, what's the president saying but looking at the big picture about sondland now? here. >> changing his tune on a not we know these hill committees were seeking out bolton's surprisingly from what he's said testimony but didn't want to go before when re viewed sondland's to the courts for it. essentially, this is saying, testimony more favorable to him. that they will have to, because after the revision, sondland lawyer says he will not testify told house investigators he unless a court ordered him to do actually suddenly recalled so. pulling aside a ukrainian now the hill committee has to official in september saying if come up with an idea to decide