29 CFR Part 1630, Regulations to Implement the Equal Employment Provisions of the ADA (Title I Regulations with amendments issued through May 2016)

(d) An individual with a disability is not required to accept an accommodation, aid, service, opportunity or benefit which such qualified individual chooses not to accept. However, if such individual rejects a reasonable accommodation, aid, service, opportunity or benefit that is necessary to enable the individual to perform the essential functions of the position held or desired, and cannot, as a result of that rejection, perform the essential functions of the position, the individual will not be considered qualified.