$ sudo apt-get remove corosync 

Uninstall corosync including dependent package

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

$ sudo apt-get remove --auto-remove corosync 

Use Purging corosync

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

$ sudo apt-get purge corosync 

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 corosync 

See Also,