Database
[/** 1*/{"_id":"61264e2dc0e8b5b3daa16c9a","orderNumber":"100","__v":0,"items":[{"itemId":"I000005","region":["US","EUROPE"]},{"itemId":"I000006","region":[]},{"itemId":"I000007","region":["JAPAN"]}]},{"_id":"61268283c0e8b5b3daa1f245","orderNumber":"101","__v":0,"items":[{"itemId":"I000008","region":[]}]},{"_id":"61268283c0e8b5b3daa1fg3c","orderNumber":"102","__v":0,"items":[{"itemId":"I000009","region":[]}]}]
Query
db.collection.update({orderNumber:"100"},{$pull:{items:{itemId:"I000007"}}})