Amending 2006 return with change in "Status" to Head of Household help?

I am amending my 2006 return, as I did not put that I was head of household. I have a qualifying relative -my daughter - who was 25 April 10th, 2006. I cannot claim her as a dependant since she does not meet all the requirments, so my exemptions stay a 1... However she was a "qualifying relative", becasue she did not earn more than $3100 in 2006, was temporarily away at school, and I paid more than 1/2 her support for the year. So this I all know. I am doing the 1040X, but do not know where to show the change in status, and how to compute the refund I should? be due. Where on the 1040X do you give this information? Or do you just add the info on the back of the form and the IRS computes it? Many thanks.