While former NBA star Lamar Odom lay in a coma in a Nevada hospital, it was his estranged wife, Khloe Kardashian, who held the legal right to make medical decisions for him, despite the fact the couple had signed divorce papers (their split was not yet final).

Apparently Odom had not thought to designate someone else to have medical power of attorney over his health care, leaving his not-yet-ex-wife in charge by default.

Do you know who would be in charge of your care in you became too incapacitated to express your wishes?

In some states, medical power of attorney is known as durable power of attorney for health care, but the process of assigning someone to make medical decisions for you if you can’t make them yourself is basically the same.

It’s crucial to do this because it gives you control over your treatment and, if necessary, how you end your life.

Choosing a trusted friend or loved one to serve as your health care agent ensures your wishes are followed and not left to doctors’ interpretation. Would you wish to be fed through a tube or connected to breathing equipment indefinitely? What if you become estranged from your spouse and, like Odom, are moving toward divorce? Would you want your (perhaps unfriendly) soon-to-be ex to make life-or-death decisions on your behalf?

Related: Advance Directives: The Documents That Let You Die with Dignity

According to the American Bar Association (ABA) and Nolo Press, which publishes legal forms and software, these are the steps you should take to designate someone to have power of attorney for your health care.

Don’t delay. Planning medical decisions in advance can take the burden off loved ones, who will be overwhelmed if anything happens to you.

Choose carefully. Trust in the person is critical, as your life could be at stake. The ABA advises picking someone who lives nearby or can travel easily, who will listen to and understand your wishes and who can stand up to conflicting opinions from family members, doctors and other medical staff.

What are your wishes? Decide what kind of guidance you want to give, then discuss it with your the person you choose. Go over special instructions and any limitations on the power you bestow. Decide what sort of care you’d wish to receive as well as any treatments or life-prolonging care you would not want.

Related: Why You Need an Advance Directive, and How to Create One

Know your state’s requirements. Some states do not honor universal forms, so it may be necessary to complete paperwork specific to the state you live in. Contact your local legal aid office, health department or state advocacy organization for the aging for information specific to your state. Courts rarely step in to adjudicate these documents unless they are filled out incorrectly and might be ruled invalid. If in doubt, have an attorney or legal aid office review your paperwork before you sign anything. In Missouri, North Carolina, South Carolina and West Virginia, power of attorney forms must be notarized.

Complete the paperwork. Forms specific to your area can be obtained online through health departments or your state bar. If you are scheduled for a potentially life-threatening procedure, the hospital may be able to help you complete a medical directive form prior to surgery. You will need to fill out the form and sign it in the presence of two witnesses, both of whom must be at least 18.

Make copies and distribute them. Give a copy to your health care agent as well as to your doctor or regular health care provider. Some state health departments maintain a registry of advance medical directives that physicians can access online. If yours does, you may want to file your paperwork with the registry. Keep your own copy in a fireproof lockbox or safe.

This paperwork is the final word. If you ever need to make a change, you must complete and sign a new form and destroy all copies of the old one.

Related: 6 New Year’s Health Resolutions You Can’t Afford Not to Make

Steve Evans, MA, is an award-winning journalist with more than 20 years experience in daily news, investigative, health and business journalism. Among other jobs, he has served as managing editor of the Central Virginia Newspaper Group, as a senior writer for SNL Financial and as a staff writer for The Progress Index and the Richmond Times-Dispatch.