How to replace a hash key with another key

Question

I have a condition where, I get a hash

  hash = {\"_id\"=>\"4de7140772f8be03da000018\", .....}

and I want this hash as

Answer 1

If we want to rename a specific key in hash then we can do it as follows:
Suppose my hash is my_hash = {'test' => 'ruby hash demo'}
Now I want to replace 'test' by 'message', then:
my_hash['message'] = my_hash.delete('test')