I own a commercial property with my brother and sister. My brother lives in Australia and I was wondering if there is a way I can sign legal documents, such as leases, on his behalf? Is it a form of power of attorney that I need? What we have been doing for some years is when we do a new lease we email it to him, he prints it off and signs it then posts it back to us. It's all a bit of a faff and I was looking for an easier way of doing things.