How to cancel update messages from a changed plugin

The quick and easy method to do this is to edit the Version.
For example if the version no. is 1.1.2 edit to make it to 100.1.2.
Hence your plugin will not ask you to update itself unless it reachess the version no. 100.1.2.
You can edit this version no. in the plugins main php file.

 <?php
  /**
  * Plugin Name: Name Of The Plugin
  * Plugin URI: http://URI_Of_Page_Describing_Plugin_and_Updates
  * Description: A brief description of the Plugin.
  * Version: 100.1.2
  * Author: Name Of The Plugin Author
  * Author URI: http://URI_Of_The_Plugin_Author
  * License: A "Slug" license name e.g. GPL2
  */