如何将数据从表单传递到另一个先前从任何其他表单实例化的表单？

I have three forms(form1,form2,form3), my main form is form1, from that i opened form2 taking some data and i have an update button on form2 that will take me to form3, now i want that whatever user writes on form3 is updated to form2, how can i make it possible using c#.net?I have three forms(form1,form2,form3), my main