Resetting Apple ID box on App Store Updates

Hi, When I try to update software on the App store, the login box is greyed out with a user ID that is very old. I can't put in my current Apple ID and my current password is rejected. This happens only with software updates. Everything else takes my current Apple ID and password. I checked my Apple ID info page and it's all the current info, but that old ID still shows up with Updates. How can I get to the Apple ID box to put in my current info?