I want to upgrade my extension on magento connect. Please describe the process to upgrade any extension on magento connect.
I also want to know the process to make the extension PAID. please describe.
You can update your extension via the Versions Tab by uploading a new version of the extension. If you would like to edit the profile that can be done by going to your magento.com account > Manage Extensions > Edit.
If you want to make the extension paid just uncheck the free box and add a link to the Landing URL.
Hope that helps!
The easiest way is override all files of extension. But in the most case, to make sure you do the right way, you should contact the owner of extension to make sure it work. Remember backup before update.