An option to transfer between Legacy and Destiny (or vice-versa) has been implemented.
However, it has several restrictions. First of all, this is a purchasable via premium section only service.
It means that it cannot be paid with medivia coins or to be purchased within the game itself from other players.
Another restriction is that if you try to transfer your character again within less than 180 days from the last transfer it will require double service of that kind.
Also, transfer is visible on the character page. You can see there how long ago character did transfer and from which world.