Close a page before opening the same page (if the page is previously opened)

Hi!
I am using asp.net to call the reporting servces report. In my asp.net page, there is a parameter screen which while running opns the reporting services report in asp.net page as pageA.aspx
Now, whenever, i again change the parameters on the parameter page and click the run button, if pageA.aspx is already opened, it just refreshes that page but the page doesn't generate new results ( caused by the change in parameters).
I want to close that page  (pageA.aspx) before generating the same page with other values (caused by the change in parameters in parameter page).
I want this function in page_load() function of the param page.
Any idea plz???
 
 
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