If Shulkin, the only holdover from President Barack Obama’s administration, was fired, the actions of his acting replacement — Defense Department official Robert Wilkie — could be legally challenged as invalid until Trump’s permanent pick for the job, White House doctor Ronny Jackson, is approved by the Senate. If Shulkin resigned, Trump can put his own candidate in place to assume the job.

The White House, now seemingly aware of the issue, has maintained that White House chief of staff John Kelly offered Shulkin the chance to resign in a conversation a few hours before Trump tweeted that he was replacing his VA secretary.

Shulkin, on the other hand, has vehemently denied that he resigned, telling multiple outlets that he was flatly fired.

Everything we know about Shulkin’s White House exit – CNNPolitics

hmmmm