Node js, Firebase - how to change corresponding nodes?

I can query a Firebase Database and get a snapshot. I can parse the JSON file. But I cannot get the 'email' node & key and the corresponding 'status' node & key.

Once I am able to get the 2 corresponding children, how to I change their values and update them to the Firebase Database?

"users" : {
  "user1" : {
    "email" : "me@gmail.com", 
    "status" : "I LOVE TO PROGRAM"
  },
  "user2" : {
    "email" : "hello@gmail.com",
    "status" : "i now love you"
  }
}

How to...?

Query: user1/email & user1/status

Change: user1/status and update Firebase.

via Christian B