Larian Studios Forums Divinity: Original Sin 2 - The Modding Dungeon Divinity - Original Sin 2 - Modding Guides Tutorial - Companions/Party management via dialog.

I believe all you need to do is is change the 2 procedures to make the NPC a "follower" and to "unfollow" when you ask them to leave.

CharacterIsPartyFollower(_Char);
CharacterStopFollow(_Char);



// Procedure to add an NPC you are talking to the party.(as a follower)
PROC
PROC_AddPlayerToParty((CHARACTERGUID)_Char)
AND
CharacterGetDisplayName(_Char, _, _name)
AND
StringConcatenate(_name, " Has joined your party",_MsgDisplay)
THEN
DB_IsPlayer(_Char);
CharacterIsPartyFollower(_Char);
ShowNotification(_MsgDisplay);

// Procedure to remove NPC you are talking from the party as a follower
PROC
PROC_RemovePlayerFromParty((CHARACTERGUID)_Char)
AND
CharacterGetDisplayName(_Char, _, _name)
AND
StringConcatenate(_name, " Has left your party",_MsgDisplay)
THEN
NOT DB_IsPlayer(_Char);
CharacterStopFollow(_Char);
ShowNotification(_MsgDisplay);