Hi all I have a question regarding with dropdown combo. May I know how to view back the data at dropdown combo so that I can edit it?

Example here:
I have saved the data about my personal. In that form I have selected the wrong country. Then I want to view this data to edit the country. What I cannot do is I want to display the previous country that I selected before at that dropdown combo. Can someone please tell me the simple way how to do it?

Thanks