On Tuesday, Trump announced on Twitter he was firing John Bolton:

Donald J. Trump

?@realDonaldTrump

 · Sep 10, 2019

I informed John Bolton last night that his services are no longer needed at the White House. I disagreed strongly with many of his suggestions, as did others in the Administration, and therefore.....I asked John for his resignation, which was given to me this morning. I thank John very much for his service. I will be naming a new National Security Advisor next week.

Bolton claimed he planned to resign.

John Bolton

?@AmbJohnBolton

I offered to resign last night and President Trump said, "Let's talk about it tomorrow."