Reasonable Accommodation & Religion
The law requires an employer to reasonably accommodate an employee's sincerely held religious beliefs or practices, unless doing so would cause difficulty or expense for the employer. This means an employer may have to make reasonable adjustments at work that will allow the employee to practice his or her religion, such as allowing an employee to voluntarily swap shifts with a co- worker so that he or she can attend religious services.
Title VII defines “religion" to include “all aspects of religious observance and practice as well as belief."  Religion includes not only traditional, organized religions such as Christianity, Judaism, Islam, Hinduism, and Buddhism, but also religious beliefs that are new, uncommon, not part of a formal church or sect, only subscribed to by a small number of people, or that seem illogical or unreasonable to others.  Further, a person’s religious beliefs “need not be confined in either source or content to traditional or parochial concepts of religion."  A belief is “religious" for Title VII purposes if it is “‘religious’ in the person’s own scheme of things," i.e., it is “a sincere and meaningful belief that occupies in the life of its possessor a place parallel to that filled by … God."  An employee’s belief or practice can be “religious" under Title VII even if the employee is affiliated with a religious group that does not espouse or recognize that individual’s belief or practice, or if few – or no – other people adhere to it. 
Sincerely Held(as defined by the EEOC Compliance Manual):
Title VII requires employers to accommodate only those religious beliefs that are “sincerely held."  Therefore, whether or not a religious belief is “sincerely held" by an applicant or employee is only relevant to religious accommodation, not to claims of disparate treatment or harassment because of religion. In those claims, it is the motivation of the discriminating official, not the actual beliefs of the individual alleging discrimination, that are typically relevant in determining if the discrimination that occurred was because of religion. A detailed discussion of reasonable accommodation of sincerely held religious beliefs appears in § IV, but the meaning of “sincerely held" is addressed here.
Like the “religious" nature of a belief or practice, the “sincerity" of an employee’s stated religious belief is usually not in dispute. Nevertheless, there are some circumstances in which an employer may assert as a defense that it was not required to provide accommodation because the employee’s asserted religious belief was not sincerely held. Factors that – either alone or in combination – might undermine an employee’s assertion that he sincerely holds the religious belief at issue include: whether the employee has behaved in a manner markedly inconsistent with the professed belief;  whether the accommodation sought is a particularly desirable benefit that is likely to be sought for secular reasons; whether the timing of the request renders it suspect (e.g., it follows an earlier request by the employee for the same benefit for secular reasons); and whether the employer otherwise has reason to believe the accommodation is not sought for religious reasons. However, none of these factors is dispositive.
Religious Accommodation (as defined by the EEOC Compliance Manual):
A reasonable religious accommodation is any adjustment to the work environment that will allow the employee to comply with his or her religious beliefs. However, it is subject to the limit of more than de minimis cost or burden. The need for religious accommodation most frequently arises where an individual’s religious beliefs, observances, or practices conflict with a specific task or requirement of the job or the application process. The employer’s duty to accommodate will usually entail making a special exception from, or adjustment to, the particular requirement so that the employee or applicant will be able to practice his or her religion. Accommodation requests often relate to work schedules, dress and grooming, or religious expression or practice while at work.