 For the human variation model, reasonable accommodation requires changes in the physical and social environment, from installing ramps to modifying work schedules and altering the location of meetings and classes. Often, such changes require little more than flexibility and imagination. But some of these changes can be expensive; at some point, the cost may make further change unreasonable. On this approach, the legislative understanding of such accommodation as a matter of distributive justice is reflected in the qualifying use of “reasonable” and the exemption of accommodations that would impose an “undue” burden or hardship on the entity required to make accommodations (Wasserman 1998).