[{actions:[{_id:ObjectId("641b34b7aa7f4269de24f050"),participants:[{_id:ObjectId("641b33c3aa7f4269de24ef10"),referenceId:"641b3414aa7f4269de24efa5",name:"Person one",email:"example@gmail.com"},{_id:ObjectId("61bb9105362e810ae9a6826f"),referenceId:"641b3414aa7f4269de24ef4g",name:"Person two",email:"example2@gmail.com"}]}]}]

db.collection.update({"actions.participants.referenceId":"641b3414aa7f4269de24efa5"},{$set:{"actions.$[action].participants.$[participant].name":"Person 1"}},{arrayFilters:[{"action.participants.referenceId":"641b3414aa7f4269de24efa5"},{"participant.referenceId":"641b3414aa7f4269de24efa5"}]})