(Thanks to D Klempa and Doyle Tavener for the corrections to this.)
The "Overcoming Melancholy" rule is a badly written rule. It is reaches too far, is too complex, and fails. Here is one I am experimenting with. Give it a try, report your results here (or to me privately).
The basic idea is that an outsider can try to shock a person out of a profound emotional state. These states include melancholy, madness or the senseless bliss of love that overcomes amorous knights.
I use the term Victim for whomever is in the profound state, and Healer for the person who is attempting to fix the other one.
With the Gamemaster's approval, the healer may use a different passion that the victim's, if both player and Gamemaster think a different passion more appropriate. However, the use of a different passion by the healer may incur a penalty to the passion score (-5 or -10).
The process is an opposed resolution of the Passion which the Victim failed (or fumbled) to bring on the state, and the Healer's same Passion. This does not have to be a passion for the same person, but it must be the same passion. Thus anyone can use their Loyalty (Lord) if the victim fumbled that, even though they have different lords.
Snap Out of It!
Both attempt their Passion.