Of course, any other ending for Saki's cleverly plotted story "Dusk" with its satiric surprise ending will not measure up to the original, there are some choices that the writer of this new ending can make.
Perhaps in keeping with Saki's satire of Norman Gortsby's cynicism, the ending could be altered by leaving the ending that is the orginal, but adding to it: Gortsby continues to sit on the bench a while, berating himself for thinking that he should "not be too clever in judging by circumstances" and then discovering that he was right after all as the soap did not belong to him, but to the elderly gentleman. Then, he holds his head and emits a low moan.
One evening of the following week, Gortsby "counts himself among the defeated" in judging human nature. As he sits in the shadows, the young man happens by. For a moment, he hesitates, again there is "a catch in his voice" as he addresses Gortsby as "Sir."
When Gortsby recognizes the young man, he turns to him and makes a cynical remark (use dialogue here); the young man responds that he wishes to repay Gortsby, explaining that he felt guilty taking the money. (Put all this in dialogue) He quickly repays Gortsby the sovereign and hurries away. Now, Gortsby must readjust his opinion a third time. (Write his thoughts.)
If the young man returns the money, Gortsby is, in a sense, defeated in his renewed cynicism and feels confused. How will he know how to trust anyone again? Yet, he should trust people if this young man has returned. He sits down again on the bench, holding his head.