Intransitive verbs cannot be used in the passive
Incorrect : She was disappeared from the house.
Correct : She disappeared from the house.
Incorrect : An accident was happened there.
Correct : An accident happened there.
Incorrect : The tragedy was occurred only minutes after take-Off.
Correct : The tragedy occurred only minutes after take-off.
Note: "Disappear”, “happen' and "occur' are intransitive verbs. Such verbs cannot be used in the passive voice.