Drain and refill, you will need a service manual and the proper crush washers, Honda Manual transmission fluid, and a funnel with a hose to refill. See the dealer for the MTF and crush washers, Helm.com for the service manual, and an auto parts or hardware store for the funnel with the hose end.
If its only a one shot deal it sould be cheaper to just take it into a shop but they use or you provide the Honda MTF and yes it's that good.