Open your plesk panel by http://:8880 i.e for Domain godavari.ewebguru.net it will be http://godavari.ewebguru.net:8880
After Successful Login You will see following link into your home page on left Top
Click on Domains
->You will see your domain name (One or more as per your plan)
->Now click on domain name which FTP Password you want to change,
-> You will see many icons one of them will be similar to (Location on top right)
Web Hosting Settings
After clickin this icon you will see
FTP/Microsoft FrontPage Login
And you have option to reset your FTP password
Provide new password and confirm password click on OK button.
Your ftp password has been reset