In order to change the information of your FTP service in Plesk, take the following steps:
1. Log into myTophost Panel and select Plesk Login in order to connect to the Plesk of the plan that you are interested in.
2. In the tab Websites & Domains, click on Web Hosting Access.
3. In the fields Password and Confirm password enter the new password and click on ΟΚ.
Note: The password must consist of numbers, symbols and letters.