Modifying the order after checkout

Hi,

I have recently ordered for some products and checked them out too. However I wish to modify my order as I have mistakenly ordered for more quantity than i need. Also I want to add some other products. I have not yet received any acknowledgement of the order or any intimation that it has already been shipped.

How do i do this on sparkfun website ??

All i can do right now is view my order.