Even those listening should fold their kosher Megillahs. We make sure to bang when Haman's name is mentioned. Some words are repeated in the Megillah. The blessing "Harav" etc. after the Megillah is said even without a minyan. The Rebbe read the Megillah for the Frierdiker Rebbe.

https://www.torahrecordings.com/shulchan_menachem/orach_chayim/347_001