In English the passive is formed by using,
Subject + [the appropriate form of the 'be' verb] + the past participle.
be - is being was/were been
A. Someone had canceled the meeting.
A. The meeting had been canceled, and I don't know why.
The appropriate form of the 'be' verb is 'been' because that is what the past perfect would use.
B. Someone has dismissed the class.
B. The class has been dismissed; therefore, I am at home now.
C. Someone dismissed the class. (past tense active)
C. The class was dismissed.
D. Someone is dismissing the class right now. (present continuous)
D. The class is being dismissed.
E. Someone dismisses the class everyday at 3:30 PM.
E. The class is dismissed everyday at 3:30 PM.
Here are some new ones to try. Try to follow the patterns in the examples above. We'll get you straightened out on this.
A. Someone has stolen the jewels.
A. The jewels
B. Someone had stolen the jewels.
B. The jewels
C. Someone is peeling the potatoes.
C. The potatoes
D. Someone peels the potatoes everyday
D. The potatoes
E. Someone was peeling the potatoes.
E. The potatoes