Thank you so much guys for your simple help.
I was trying so many ways to get a one way ticket on Us airways
if you book through us airways or continental they make you book a round trip. so the only option was to do it through united but spg is 2 to 1 and amex only transfers to continental, and I did not realize it's so simple to just transfer amex to continental and then you transfer that to united. and there you go. Got my one way ticket 12,500 points. THANKS EVERYONE