As long as there is no significant increase in duties and requirements are reasonable and legal, an employer can make changes to your job description. Your employer should discuss any changes with you first. If you think you might be being discriminated against, seek legal advice.
Can they change your job title?
Can an employer change your job title? “According to the Society for Human Resource Management (SHRM), a company can change your job title at any time, provided there aren't clauses in the employment contract that state otherwise,” Doody said.