Trading can be performed with named characters by pressing 2 on the Wii Remote or Y on the Classic Controller and New 3DS while the party leader is next to them. The characters carry a variety of items that can be traded, and there is no limit to how many times items can be traded for. One item that the person has available for trading must be chosen, and an item of equal or greater value must be offered in return. There are certain skills that can raise the trade value of items given in trade.
Characters will have more items available for trading as the party's affinity with the area increases. Items an individual character has available to trade may change if he or she relocates to a different location, either permanently or temporarily during a quest.
The trade value of Materials is equal to the item's Sell Price (excluding Riki's "Buy Stuff!" skill bonus), while the trade value of Weapons, Armour, and Collectables is ten times the item's Sell Price.
Two skills increase the value of items which the party offers for trade:
Riki's "Friends Now!" skill in his Vivacity tree adds 5%.
Shulk's "Hero's Privilege" skill in his Bravery tree adds 20%.
Once unlocked, these skills are always in effect for the entire party. They cannot be linked, so the maximum combined bonus is 25%.
All characters have a bonus item that can be received through overtrade. It is received by the party as a bonus during trading if the value of the item being given by the party is equal to or greater than the comined value of the requested item and the overtrade item.
For example, Dorothy's overtrade item is a Giant Hornet with a trade value of 1,800 G. If the party trades for a Small Shell which has a value of 100 G, they must offer an item worth at least 1,900 G to receive both the Small Shell and the Giant Hornet.
The collectables on the Other Collection page of the Collectopaedia can only be received through trading with certain characters, and usually after certain conditions have been met. These collectables tend to be much more expensive than most other items, with some only being obtainable through trading with very rare materials and with both of Riki's and Shulk's trading skills unlocked.
Xenoblade Chronicles 2
Trading can be performed with named characters displaying an "over-poise" icon above them.