1.       Find out the line number you want to remove

# history

  987  2014-04-07 14:03:19 apachectl stop

  988  2014-04-07 14:09:49 apachectl start

  989  2014-04-08 13:09:54 apachectl stop

  990  2014-04-08 13:11:24 apachectl start

  991  2014-04-08 13:11:27 exit

2.       Now delete the line from history by command history -d #. Example here I am going to delete line 990

# history -d 990

3.       Check the line has been deleted or not

# history

  987  2014-04-07 14:03:19 apachectl stop

  988  2014-04-07 14:09:49 apachectl start

  989  2014-04-08 13:09:54 apachectl stop

  990  2014-04-08 13:11:27 exit

  991  2014-04-11 17:26:44 history -d 990

  992  2014-04-11 17:26:47 history

If you want to use everything from history then use following command:

# history –d