[{_id:ObjectId("647b1538c29a553ad6e8f316"),label:"Name",itemId:ObjectId("647b1538c29a553ad6e8f313"),formId:ObjectId("647b1538c29a553ad6e8f913"),value:"ABC"},{_id:ObjectId("647b1538c29a553ad6e8f416"),label:"Email",itemId:ObjectId("647b1538c29a553ad6e8f313"),formId:ObjectId("647b1538c29a553ad6e8f913"),value:"def@mail.com"},{_id:ObjectId("647b1538c29a553ad6e8f516"),label:"Name",itemId:ObjectId("647b1538c29a553ad6e8f320"),formId:ObjectId("647b1538c29a553ad6e8f913"),value:"MNO"},{_id:ObjectId("647b1538c29a553ad6e8f616"),label:"Email",itemId:ObjectId("647b1538c29a553ad6e8f320"),formId:ObjectId("647b1538c29a553ad6e8f913"),value:"xyz@mail.com"}]

db.collection.aggregate([{"$match":{"value":"ABC"}},{"$lookup":{"from":"collection","localField":"itemId","foreignField":"itemId","as":"results"}},{"$unwind":"$results"},{"$replaceRoot":{"newRoot":"$results"}}])