Kelley Elliott, the principal accounting officer and controller at Express Scripts, has resigned from the company, effective Sept. 27, due to personal reasons.

“Ms. Elliott's departure was not due to a dispute or disagreement with the company,” Express Scripts announced in a Form 8-K filing with the Securities and Exchange Commission. “The company has initiated a search to identify a replacement principal accounting officer and expects to conclude the search process expeditiously.”

Elliott joined Express Scripts in 1999. She served in the internal audit department from 2002 to 2005, and held other senior management positions, including vice president of internal audit services, principal accounting officer and controller. Earlier in her career, she served as an auditor at Ernst & Young.