Well, you can't the only way to evolve eevee into leafeon is to level it up in Eterna Forest in either Diamond, Pearl, or Platinum.
It is the same way with evolving eevee into Glaceon.
Level it up on Rt 214.
It cant
You have to get it from a friend who has Pearl/Diamond/Platinum
you cant get glaceon or lefeon in soulsilver
Vulpix, Growlithe, and Eevee.
Vaporeon doesn't evolve. If you mean how to get it from Eevee, use the water stone.
It cant only by training it in diamond, pearl, and platinum
Can only evolve from Eevee if it gains a level while on Route 217, so you must trade an Eevee over to Diamond, Pearl, or Platinum and evolve it there, since there is no Route 217 in HeartGold and SoulSilver.
you must get an eevee from bill in kanto and with a firestone it will evolve into flareon
Evolve from Eevee by happiness at day time.(4:00am to 8:pm)
talk to your eevee if it gives you a hug it should evolve plus if you want to speed up this proccess use a soothe bell
There is a moss rock, you level up your eevee around the stone, doesnt matter how many levels, eevee will evolve at the end of the battle
You cant evolve it into glaceon unless you bring an ice stone over from a game that has more stones than silver, (silver doesn't have to many.) after transferring it, eevee will evolve. The best you can do without an ice stone is espeon(if it evolves in day) or umbreon (if it evolves in night).