Want to add contents in Confluence page using REST API

[Kunal_Shah]

Hello,

I have a confluence page. It consists some data.

I want to update the contents of the page without changing the existing contents/data.

Example: 

My confluence page have content: Hello World!

I want to update page contents and finally it would be like:
Hello World!
New data


The Confluence API : https://developer.atlassian.com/cloud/confluence/rest/#api-api-content-id-put replaces the entire contents of the page.

How can I just add new contents into the page keeping it's existing content using REST API?