Yes, as a general matter, they may take a day's salary away. A salaried employee may not have his or her pay reduced for missing hours or part-days of work, but if he or she works whole days less, the employer may reduce his or pay commensurately. Also, as a general matter, an employer could reduce your salary, change your hours, shifts, job description, etc. at will , which means it just re-define you as 3-day-per-week employee earning, for example, 75% as much as previously.However, if you in fact had a written employment contract, you may enforce its terms, and the employer may not reduce your pay in violation of it.