PDF overlaps the app and unable to dismiss the pdf using appium

In a certain workflow my app in test pops up a document viewer pdf, and workflow demands the pdf to be dimissed. If any one can share some ideas on how to dismiss the pdf report using appium…
I am Java with appium, if that matters.

Does that popup have some close button if not that you can try driver.navigate().back() in android method to dismiss the popup and for ios you need to click some
outer element on screen.