How to change directory for uploads in Your WordPress?
Please to edit the wp-config.php file located in the root directory of your WordPress (on your ftp). For example if you want change the uploads loacation from "example.com/wp-content/uploads/" to "example.com/photos/" then put the following code in wp-config.php
define( 'UPLOADS', ''.'photos' );
How to remove month and year subdirectories?
If you want to additionally remove data/month subdirectories then please go to Settings -> Media and uncheck the option "Organize my uploads into month and year-based folders".