changing the first hub on a NH 7230 discbine

I am getting the 7230 discbine  ready for the season and I am trying to figure out how to remove the blade hub from the first cutter bar section, the one that connects to the drive shaft. I changed the blades without removing the hub but was wondering how to do if it ever becomes necessary do it. I suppose I would go to my old standby and just take it to the dealer let them fix it. Thanks in advance

changing the first hub on a NH 7230 discbine