The employment laws on changing a job description favor the employer in most situations. Generally speaking, an employer can change a job description whenever it is convenient to the company. In some situations, a change of job description requires negotiation with the employees or with a union.

When Job Descriptions Are Protected

Job descriptions and the employees who fulfill them are protected when a formal employment contract has been established. Written employment contracts may contain language that specifies a job role and duties but often focus on salary, benefits, work location and title. When signing a contract, prospective employees should ask for language that spells out what role they are expected to fulfill and whether or not that role can be changed without notice. Corporate needs change, and companies have a right to change job descriptions accordingly.

Contracts That Protect Employees

Employment contracts that have been negotiated through a union normally contain stipulations that protect the rights of the employee from arbitrary and capricious changes in the conditions of employment. A breach of contract can occur if an employer changes a job description without renegotiating with the union. Negotiations are usually done on regular timetables, which limits the opportunity for employers to change established roles quickly.

Protections Afforded by Special Interest Law

Employment laws developed for protected or special interest groups can shield employees from specific changes in their job descriptions. An employer cannot break any law in an attempt to change a job description. For example, the Americans With Disabilities Act protects disabled persons in the workplace. A job description change that forces an employee to work in a capacity in which he is unable to physically perform would be illegal.

Job Description Best Practices

Most employment relationships are considered "at will," meaning the employer can reasonably let an employee go and an employee can leave at her own discretion. Best employment practices regarding job descriptions call for supervisors to keep job descriptions up to date by involving the employee in any desired changes. Minimally, an employee and supervisor should meet annually to discuss the job description, likely on the occasion of the performance appraisal. Where the law doesn't specifically provide guidance, common sense and actions consistent with employment laws promote healthy employer-employee relationships.