In any county to which Section 6-30 applies, no person may serve on a board of review who has not passed an examination prepared and administered by the Department to determine his or her competence to hold the office. The Department shall conduct examinations for various counties in a convenient location in the region. A candidate appearing at the examination shall indicate to the Department the name of the county the results shall be certified to if he or she successfully passes the examination. The Department shall certify the list to each county from which candidates have appeared at the examination location. Within one year after the effective date of this amendatory Act of 1997, the Department shall conduct an examination at least once in each commission county for which the chairman of the County Board of Commissioners requests an examination. The Department may provide by rule the maximum time that the name of a person who has passed the examination shall be included on a list of persons eligible to serve on the board of review.