Is it possible to flash a iPhone 4s from sprint to boost?

I have a iPhone 4s my aunt got a upgrade and gave me her old iPhone. So now I want to turn it on using boost is it possible for me to flash it in stores and if it isn't can you let me know if there's any other ways

Should be able to starting since last year.
Best luck.
http://www.phonearena.com/news/Sprint-phones-are-now-welcome-on-Boost-and-Virgin-Mobile_id40537

http://www.sprint.com/...stlanding/

Its not