The Department of Education has announced plans to lay off 50% of their workers. What impact will this have?

Per a news article:

Senator Bill Cassidy, Republican of Louisiana and the chairman of the Senate Committee on Health, Education, Labor and Pensions, wrote on social media that he had spoken with Ms. McMahon and received assurance that cuts would not affect the department’s “ability to carry out its statutory obligations

If a Department can meet it's statutory obligations with 50% of it's staffing level, what were the other people doing?