Hi Bhat,
I don't know if it is possible to open it in the same Page. But you can try using the Opendoc Parameter which allows you to enable you to pass the credentials you have used in the current Dashboard.
A useful link,
https://help.sap.com/businessobject/product_guides/boexir4/en/xi4_opendocument_en.pdf
Regards,
Fazith Ali Z