Dear PAO,

I am currently living in Manila, but I own a parcel of land in Bacolod, where my sister resides. I recently visited Bacolod to see if I can develop that parcel of land for additional income. However, I learned that my sister sold my land to a third person. The buyers claimed my sister told them I authorized her to sell my land. I remember that we talked about it, but my instructions were clear that my sister should wait for my final decision to sell the land. I did not execute any written document that would authorize her to sell the land. I want to know if such a sale is valid.