Pinkpalace, if you know for sure what date or around what date you ovulated and concieved they may consider changing it, but usually if its within 7-10 days they wont bother. My EDD is 2/11 but i know i didnt ovulated til a week later than normal and bubs is measuring 7/11 but they wont change it cause its within the 7-10 days of the EDD but your the patient so demand it.