Using the below command to remove the application completely from any Debian based operating systems

sudo apt-get purge [packagename]
sudo apt-get autoclean
sudo apt-get autoremove

Note: remove the package name with application name going to remove

Open a terminal and enter sudo -s to enable the root privileges.

user@user-pc:~$ sudo -s

Next, edit the hostname using the below command

root@user-pc:~$ nano /etc/hostname

It will show the existing hostname (PC name). Now you can edit it and save using ctrl + x command.

Once restart your PC your hostname (PC name) will update automatically.