I moved your post into this thread as it appears to be the same question
We just had a related conversation about this topic here that might interest you: 
I would disagree, this is not what a walk in is. You have to evict a being from his vessel, which requires permission you probably won’t have, and then you have to leverage yourself out of your current vessel, and stay clear and know how to take the other body. The combination of skills for this would take decades to figure out and there’s pretty much no-one that knows how, you’d be a pioneer and the whole thing would be very experimental and high risk.
I actually think they could, but how are you going to make contact and ask them and … hope to get free shit from them? They may also disagree with your motives if it’s cosmetic rather than to cure a disability, say. All ETs are not equeal either so it depends who you talk to. You could end up being used if you get in with the wrong crowd.
No, the human form is camouflage tech not real. Some ETs, notably the greys make “biosuits” and transfer their consciousnesses to those to live for thousands of years. The biosuits tend to be specialised for the job they do. But they are Grey species biosuits not human suits. Humans are more complicated and the best way to make them is to grow an human from a human fertilised egg… Imo.