The employer must show that it cannot reasonably accommodate the employee’s religious practice without working an undue hardship on the employer’s business. In this case, the burden is on the employer to show that the accommodation was unreasonable that it would constitute an undue hardship.
A classic example would be where an employee’s Sabbath day for his religion falls on a Saturday. In other words, the employee’s religious practices preclude him from working on Saturdays. The employer, however, insists that the employee work on Saturdays. Depending on the particular facts at that place of employment, a court might find that the employer would have to reasonably accommodate the employee’s request and simply place the employee on shifts on other days and not require the employee to work on Saturdays.