"Ti ginesai" just like u read it!It's not actually a polite way of saying "how are you"..We almost here use it when we have to hear news by smn many days..So we see him and say "ti ginesai,pou xa8hkes?"=How are you,where are you?"It's better to say "ti kaneis;"(τι κάνεις;)=how are you? or "how do u do?"If you want to say in a polite way you can say "pws eisaste;"(πως είσαστε;) or "ti kanete;"(τι κάνετε;).