Actually, two stories.

One is similar to the Maddy Bell 'Nena' stories. A young man who looks a lot like his feckless sister gets sucked into substituting for her as a guide in a package ski tour in Europe. She is successful in the job but does confess to her manager./ All works out well, including her sister who manages to marry a rich American from LA or Los Vegas.

Another is a science fiction story. A fairly unappealing guy, I think he is a traveling sales man or tech rep, gets suckered into a Shanghai'd scenario, where someone manages a body swap with him. He wakes up as a low economic class woman, local to the planet. He/She manages to talk her ( local woman's) sister into helping her stow away on a spaceship back to earth. ( I think the sister may not understand this aspect of her plan - sister may think she is just trying to get a better job). This works, but she is caught after some period of time, 'fesses up, and things work out. She learns to be a better person along the way.

Appreciate any advice.