If you need someone to conduct your financial affairs or make medical treatment decisions for you in the future, you should consider creating a power of attorney. This is a legal document that allows someone (known as a principal) to bestow power over his or her business or medical treatment to someone else (known as an agent). You can find power of attorney forms online, and you do not need to hire a lawyer to complete one, although discussing these matters with an attorney can help you create a more effective document. To execute a power of attorney in Hawaii, you simply fill out the powers you want to grant to your agent, sign it, and have two witnesses sign the document as well.