President Trump has reportedly been calling Reince Priebus, his former chief of staff, to complain about his current chief of staff, John Kelly, in recent days. Sources cited by The New York Times on Thursday say Trump has not held back in venting his frustrations with the four-star general, phoning several people to gripe about his job performance, including Priebus—who was booted last summer after a tumultuous six-month stint. No further details were provided on Trump’s conversations with Priebus, but the president is said to have floated the idea of replacing Kelly with White House Budget Director Mick Mulvaney to some advisers. Kelly is center of the latest White House scandal, amid reports he was aware of domestic-violence allegations against staff secretary Rob Porter but failed to take action. Kelly also triggered a backlash this week by suggesting some immigrants to the U.S. are “too lazy” to seek legal status.