UNABLE TO UPDATE APPS

If you are signed in, a request for another Apple ID password is often caused by updates to apps/purchases that were made when using the other ID. Those purchases are tied to the other ID and can't be transferred. One option is to delete the apps/purchases made by the other ID and download them using the new ID if desired. After deleting the apps, it may be necessary to restart the device/computer before you can download the apps again. If necessary, check your purchases history to see which apps/purchases weren’t made by the current ID. 

Purchase History Review.  *

You need to ask the other person to sign out. If you cannot contact the other person, then you cannot use the App Store and use it as your device