Yes, In case of e-tickets booked in AC 3-tier are re-allotted in AC 3-tier economy, the difference of fare between AC 3-tier and AC 3-tier economy shall be automatically processed by IRCTC. If passenger does not want to travel in re-allotted lower class then he/she is eligible to get full refund by cancellation of ticket upto second charting of the train, or he/she can also file TDR upto 3 hours after actual departure time of the train. Passengers are requested to check their PNR status after first charting of the train and check for any SMS alerts sent by Indian Railways.