The White House is planning to withdraw the nomination of Jared Isaacman to be the administrator of the National Aeronautics and Space Administration, a White House official confirmed to POLITICO.

The sudden move comes days before the Senate was slated to vote on his nomination to lead NASA.

Isaacman, a commercial astronaut and billionaire CEO of the payment processing company Shift4, has a long-standing relationship with Elon Musk, who this week left his post as a senior adviser to President Donald Trump and chief of the Department of Government Efficiency.

It’s not yet clear what the White House’s reasoning is for the personnel change.

Semafor was first to report on the plan. The White House official was granted anonymity to discuss not-yet-announced personnel moves.

Senate Democrats for months have been critical of Isaacman’s relationship with Musk, in light of his close ties to the White House and his role as CEO of SpaceX, one of NASA’s largest contractors. 

In March, The Wall Street Journal reported that Musk personally asked Isaacman to lead the agency, which Democrats honed in on during his confirmation hearing last month.