$ sudo apt-get remove ftp.app 

Uninstall ftp.app including dependent package

If you would like to remove ftp.app and it's dependent packages which are no longer needed from Ubuntu,

$ sudo apt-get remove --auto-remove ftp.app 

Use Purging ftp.app

If you use with purge options to ftp.app package all the configuration and dependent packages will be removed.

$ sudo apt-get purge ftp.app 

If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.

$ sudo apt-get purge --auto-remove ftp.app 

See Also,