When you breed a Manaphy with any compatible Pokemon (ditto or other pokes in the same egg group) you get a Phione.
This is so you cannot get more Manaphys
beg them for a thousand years and when they are on a pheone tell them to say yes
rayquaza,groudon,giratina,shaymin,deoxys,arceus,mewtwo,mew,dialga,palkia,creselia,manaphy,pheone,azelf,uxie,mesprit,spiritomb,kyogre,darkrai,rotom.
First you have to transfer the manaphy egg from Pokemon ranger then hatch it then leave the manaphy with a ditto in the Pokemon daycare then ride your bike for a while then go talk to the guy standing in front of the Pokemon daycare and he will give you a pheone egg.
The Manaphy Egg event can be triggered at any time. This can be done by connecting the Pokemon Ranger game to your Pokemon main-series game. This only works on Pokemon versions Diamond, Pearl, Platinum, HeartGold and SoulSilver. You can then receive the Manaphy egg from a certain NPC.