it easy to do its like changing your oil go to honda get 3 quarts of honda atf drain the fluid with a 3/8 wratchet,honda will give you a gasket for the plug,drain and clean the plug ,use 2.5 quarts of fluid to fill it back up,start it up shift through gears shut it off then check fluid ,always check fluid when its off.
honda have a sealed tranny, i just bought a 99 accord with 110k dont know if tranny has ever been done but i did a drain and fill and it drive great still,there is no0 harm is draining and filling