The firts time a got the task to listen to someones plead I found the person, but wasn't able to find the option. The second time the person who wants to plead wasn't there at all, only two witnesses and random people crossing the lot. The third time finally worked.
@Edw_HareHare I cannot try out this option because my Sim lives only with three cats. Another option would be exiting the game and come back but during a mission it is not possible, only without saving. Maybe I'll try out to save before I go on the trip and if something or someone is missing I could try out to exit the game and come back.
