Close "already open pdf file" using macro made in excel 2010

Hi friends,

I am having problem in closing a "already open pdf file" using macro in excel 2010, can you guys help me in solving this.
This problem is a small part of bigger program, in which i need to replace a pdf file with new pdf (basically overwrite), but i gets error if file is already open. So i have to close pdf file first, only then my program runs.

Code that i am using is:-

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Instead this code closes my vba application and neither brings pdf window upfront.

Any help will be really appreciated.