how to cancel packages

[szhou]

   Hi, All
   I want to install ipsec-tools in FreeBSD6.3. I click command "make
   install" in directory"/usr/ports/security/ipsec-tools/", and i select
   all packages in prompted window. while the installation failed,
   because the kernel do not support one package.
   I want to install ipsec-tools without the specific package. Can anyone
   point me how to cancel the selected package? So that i can install it
   again.
   Thanks a lot!
   Shirley Zhou