To delete a policy, use the kadmin delete_policy command,
which requires the "delete" administrative privilege.  The syntax is:
     delete_policy [-force] policy_name
     
The delete_policy command has the alias delpol. 
It prompts for confirmation before deletion. 
For example:
     kadmin: delete_policy guests
     Are you sure you want to delete the policy "guests"?
     (yes/no): yes
     kadmin:
     
Note that you must cancel the policy from all principals before deleting
it.  The delete_policy command will fail if it is in use by any
principals.