Remove software

After installing application, you can use "pkg delete" command to remove it:

# pkg delete lsof
Checking integrity... done (0 conflicting)
Deinstallation has been requested for the following 1 packages (of 0 packages in the universe):

Installed packages to be REMOVED:
        lsof-4.90.b,8

Proceed with deinstalling packages? [y/N]: y
[1/1] Deinstalling lsof-4.90.b,8...
[1/1] Deleting files for lsof-4.90.b,8: 100%

You can also enter the port directory, and execute "make deinstall" instruction:

# pwd
/usr/ports/sysutils/lsof
# make deinstall
===>  Deinstalling for lsof
===>   Deinstalling lsof-4.90.b,8
Updating database digests format: 100%
Checking integrity... done (0 conflicting)
Deinstallation has been requested for the following 1 packages (of 0 packages in the universe):

Installed packages to be REMOVED:
        lsof-4.90.b,8
[1/1] Deinstalling lsof-4.90.b,8...
[1/1] Deleting files for lsof-4.90.b,8: 100%

Reference:
Using the Ports Collection.