An award or denial of award of or agreement for compensation for an occupational disease may be reviewed and compensation increased, reduced or terminated where previously awarded, or awarded where previously denied, only upon proof of fraud or under undue influence or of change in conditions, and then only upon application by a party in interest made not later than one (1) year after the denial of award, or where compensation has been awarded or agreed to be paid, after the award or the date when the last payment was made under the award or agreement, except in case of silicosis where such time limit shall be two (2) years.