When you change your character on the same account while being in a party, it would be very handy to swap your character in the party as well. This would be immensely useful for party leaders, because it means you can change your character, without passing lead around.
If "Join freely" is not enabled, only the party leader should receive this functionality, otherwise it would be useful for all characters in the party.
If the character you change to is already in another party (i.e. Permanent Party), the current behavior should be used instead. So no swapping of the character, because both characters are in a party, actually.
Right now, a party leader who explicitly created only one account with multiple characters relies on friends to toss lead around, which is suboptimal.
Thank you.