Can the will executor sell the flat that is owned by the will maker?

My neighbour who has no family whatsoever has prepared her WILL and has made me and my husband the Executors of the Will. She has given us the first option to buy the flat on her death and if we cannot afford it, then to sell it and the money to be given to charity. But once she dies, there is no owner and hence we cannot either buy or sell the flat. What do we do in such a situation? Will she have to word the WILL differently to enable us become interim owners to enable us sell the flat? Pls advise. We r Catholics.