Proper way to change the path of uploads folder for existing WordPress site

if you need to change default media upload location,you need to edit the wp-config.php file located in the root directory of your WordPress installation. If you want upload directory to be wp-content/files then you will need to place the following code in wp-config.php

define( 'UPLOADS', 'wp-content/'.'files' ); 

If you want the upload directory to be outside wp-content, like http://www.example.com/files/ then you need to set upload path in wp-config.php like this:

define( 'UPLOADS', ''.'files' ); 

For exstining images:-

Copy all the exstining images of uploads folder to new folder which has set in the wp-config.php file.

The above information is only to Change the Default Media Upload Location.