You traded ^2 for ^4.

^6 doesn’t have space to carry the ^2 that you agreed to give them

You don’t have space in your wagon to carry the ^4 that you agreed to trade for

^6 no longer has the ^4 to trade

You no longer have the ^2 to trade to ^6.

^6 ignores your offer to trade ^2 for ^4.

^6 rejects your offer to trade ^2 for ^4.

^6 gives you ^4 for ^2.

^6 would like to receive ^2 in trade