Downloading and Editing a PHP

Hi Everyone,

I'm trying to edit a .php file that needs to be downloaded from my SmartFTP. I download the file and have tried to view it in several html editors but everytime it comes up as an encoded or unreadable sequence of letters and symbols. I know which part I need to edit, I just need to see the unencoded file so I can edit it and reupload it to my FTP. Can anyone help me find a way to view and edit this file? Thank you