How do I change the apple id to update apps from Appstore on mac

you should stop giving useless answers.

I didn't become a Level 7 member of the Apple Support Communities with over 30 thousand points awarded in gratitude for my help by other community members by supplying useless answers.

Actually the OP (Original Poster) thought that I was the only one here who supplied a helpful answer.

if you put the final helpful answer as the last post instead of explaining what you did, that would be more helpful. Anyway, have to keep two accounts is not a reasonable design. it should be bind with the machine instead of an user account.

The Mac App Store and the iTunes Store work identically and the two store function as those who owned the original content that was sold by the iTunes Store, which came years before the Mac App Store, music and videos (music, movies and television programs) required Apple to sell their product, that the user licensing for the content is to the person, not an inanimate object, the Mac or iOS device. That's why the person's Apple ID is encoded in the copy that they download. Which is why the Apple ID that bought the content is the only one that can redownload or update the content, not whomever may be using the device.

I see, thanks,

but I don't think I bought iphoto and imovie, it came with the original new machine when I bought it. but when i changed to use another account. I have to keep both of them. but I have several apple products.

Will refuse to buy any apple product again. It looks not a reasonable design to me. So, never an apple product again, including the coming iphone 6 which i like most. But the software is unacceptable!

FYI. Just remove the app from your computer and re-download it with the new apple ID. worked great!

This is the most helpful answer to the question about the iphoto and the imovie update. Follow up question, did you lose all of your iphoto pics when you trashed the app?

The photos are not stored in the app bundle. Your photos are in the iPhoto library located in Users/~/Pictures

~ = username

Thanks for the reply. Let me ask the question a different way. If i trash my iphoto app, am i going to lose all my photos?

No.

Thanks! Stay tuned for more brain-buster questions when i finish the new iphoto upload.

This answer worked like a charm and was exactly what I needed. I inherited a machine that had previously been tied to another Apple ID, but no longer.

you've created a lot of necessary confusion

Yup, my thoughts exactly. I did the trash bin technique; removed all the apps that were tied to old apple id and reinstalled the ones I cared about. It worked and i have free'd up valuable MB of disk of apps I never used. Bonus.