First, find out the id of the process that is holding the lock file.
The above command will give you the PID of the processes using the lock files. Use this PID to kill the process.
sudo kill -9 PID
Now you can remove the lock and reconfigure dpkg:
sudo rm /var/lib/dpkg/lock-frontend
sudo dpkg --configure -a
Hope this helps!
Get your Linux certification today to become certified.