How do I update my apps on my Mac if the email for my Apple ID is incorrect?

My uncle bought me my MacBook Air OS X 10.9.5, it was brand new when I got it and all the logins are logged in with my Apple ID. I checked my account on my App store, and it is signed into my account too. However, I have 3 apps to be updated and whenever I click update and it asks me to put my password in as usual, it pops up with my uncles email and not mine. I don't know what I'm suppose to change considering Im already signed into the app store with my Apple ID. Can anyone tell me how to fix this?