In case you want to rename one of your files in Plesk, take the following steps:
1. Log into myTophost Panel and click on Plesk Login in order to connect to the Plesk of the plan that you are interested in.
2. Click on Files (navigate to the folder or file that you want to rename).
3. Select Rename from the drop down menu, on the right-hand side of the Group column.
4. Rename the file or folder and click on ΟΚ.