When a conversation is unassigned and an agent starts typing their response, if at the moment of sending the response the conversation was assigned to someone else (most likely because they also answered or have clearly specified they would), a confirmation would be displayed saying "Are you sure you want to send this response? This conversation was assigned to someone else since you started answering".
This could be generalized to any reassignment since started typing, with a warning saying “This conversation was assigned to {name} since you started typing your answer. Are you sure you want to send this message?”.
Or similar, you get the idea… 😉
