This page is for transferring pre-existing characters between players or Riders. If you are trying to trade an MYO, egg, slot, item, and so on--you can do that by clicking Transfer on the MYO menu or within your inventory. Please note that Hatchery eggs cannot be transferred.
Any character you own can be traded and sold for any amount (show this info to people if you'd like to reassure them!). Players ALWAYS determine the value of their own characters. However, due to the way attaching to Riders works, the system cannot handle automatic transfers for uploaded characters. They need to be manually detached to prevent errors. Because of this, they are automatically locked in the system. This is the same reason they don't automatically snap to deviantART accounts when accounts are verified/hooked up. If you would like to transfer/sell/trade dragons, you may do so here!
Eggs (also called genos or MYOs) should be transferred by players themselves. Eggs from Hatchery Quests or adopted from the Hatchery are account bound.
If you would like to transfer a dragon without their Rider (or vice versa), that dragon will be marked as 'Hibernating.' If this transfer would cause a Rider to have no dragons, that Rider will be marked as 'Hibernating,' as well. You may wake them when you attach a new companion to them.
For Prestige rank-ups, the art of a dragon will only be counted towards the level requirement if it was created while attached to the Rider. In example, if a dragon is transferred at level five, it will need 100 EXP of new art while bonded to the new Rider to count for Dragon Companion prestige.
Crafting recipes are only granted if a character in your ownership gains the class or promotion. Riders that are transferred do not automatically come with recipes, even if they have the job unlocked. You can remake the art to unlock the recipes if you would like to use a transferred crafter to gain the equivalent recipes.
If you would like to change the Rider/dragon of a character you own, rather than transfer them to someone else, go ahead and submit your new companion and upon approval their old companion will automatically Hibernate. If you would like to change Riders/dragons that you own between characters already on the Masterlist, you can comment here.
Note: Lore-wise, a dragon will die without their Rider. They cannot be mixed and matched. It is possible for Riders to survive, but it is ten times worse than missing a limb on top of the emotional loss. You are free to make your own stories, but this is what happens in canon. I recommend a clean personality wipe when you transfer dragons.