So how can I withdraw my resign letter?

Thanks everybody's input,this forum really helps!
美国老土, US老土, borisg, cater.. etc.., you guys are awesome!
Is anyway I can withdraw my resign letter, it is already turned in to the HR. Actually my big boss(my boss's boss), a really nice even told me, 'I think you make a wrong move, if you want to work for that big company, go find a full time job there, If I were you, I will keep my current job and try to find a full time job there. But I will support you whatever decision you make."