Help to Show Existing Nodes in Drop Down At the Time of Creating New Node

Hi All,
This is to ask for help in a specific situation of adding a node.
Actually, we want to develop the following functionality:
When a user is creating a node, he should be able to see the existing nodes he has already created in the drop down form along with an extra option of creating a new node.
This way, the user can either update the existing node or select the option of creating a new node from the drop down.
So, please offer your help to let us develop a functionality this way.

Drupal version: