John Franklin Ratliff, 23, 600 Grant St., changed his plea from innocent to guilty Monday in Division No. 1 of Jasper County Circuit Court to a felony charge of possession of marijuana. A pre-sentence investigation was ordered by Judge Robert Warden and sentencing was set for May 10. Ratliff is charged with possessing more than 35 grams of marijuana Aug. 6, 1972, when arrested by Carthage police. Ratliff was arrested at the Carthage bus depot while receiving a package of marijuana, which had been shipped by bus. Judge Warden overruled Ratliff's motions for suppressing certain evidence and for discovery and a bill of par ticulars. A jury panel had been assembled to hear the case, but Ratliff changed his plea from innocent to guilty after the motions were overruled.