Hello! My name is***** will work diligently to provide accurate advice and information.
Each app downloaded from the Mac App Store is tied to the original Apple ID used to purchase it. This can not be changed and the software can not be transferred to your ID, sadly. In order to remedy the situation you must delete the App and/or re-download it from the App Store. This will then allow you to update it in the future.
If you have any specific questions about doing the above, or need help signing into the Apple Store using your own ID, please let me know.