A power of attorney (POA) from your father, if he owns them personally, would work. That would give you the same authority that he has, as owner, to take action, get information, etc. in regards to the property. You don't need to use a specific form, though using a standard or commercially available POA, or one prepared by an attorney, will make sure the form is correct. You also have to make sure it is executed, witnessed, and notarized properly, so having an attorney do this for you is strongly advised.If the property is owned by an LLC or corporation you father owns, a simple letter from him, as managing member or president of the company, stating that you are the company's representative, should do. The company could even pay you, even if only a nominal amount, for your time and make you an employee or consultant.