left crankcase oil seal

Im attempting to remove the oil seal and my service manual has no info on how to remove the old seal .I removed the 6 bolts holding the seal in place and the 2 ring clips . the plate keeping the seal in place rotates but unable to pop the plate holding the seal in place.I don't want to pry to hard . Do I need a special tool to remove the seal ? Help would be appreciated  . Thanks.