How to migrate elasticsearch data

[Trung_Do]

Hi all

Now i'm using es 5.5.1 and i have requirement to migrate data.
Last month i index a data with below structure:

{
    "username": "user_03",
    "firstName":"Trung",
    "lastName":"Do",
    "post_date": "2010-11-15T14:12:12",
    "message": "trying out Elasticsearch"
  }

Now my data structure has changed to:

{
    "person": {
                    "username": "user_03",
                    "firstName":"Trung",
                    "lastName":"Do"
                    },
    "post_date": "2010-11-15T14:12:12",
    "message": "trying out Elasticsearch"
  }

Question: how can i migrate all old data from ES to this new one? I intend to use logstash to create new index and modify old data to new one by using filter plugins.
Does it support?
Can you tell me the steps to do?
Thanks