If you are the policy owner, you can change the beneficiary clause any way you want to, before you die.
You'd have your life insurance company send you the beneficiary change form, fill it out and have it notarized, and send it back to them, and they'll send you a confirmation that the beneficiary clause was changed.
You don't "exclude" people from your life insurance policy, what you do, is just fill out a new beneficiary designation form. That way, the proceeds from your life insurance go to the people you designate as beneficiaries to your life insurance. You can even designate the percentage or amount of life insurance each beneficiary is to receive.