changed my apple id now can't access iPhoto

You need to explain as no Apple ID is required to launch Photos - it is on your system locally

LN

To use applications that are associated with your old AppleID, you need to sign into the AppStore with the old AppleID, if you need to update the apps or reinstall them.

Is the problem that you need to update to iPhoto 9.6.1 and cannot?

Do you iPhoto on the Purchases tab of the AppStore, when you sign into the AppStore with your old AppleID?

You may need to unhide your Purchases as described here at this link: Mac App Store: Hiding and unhiding purchases

If you see the apps among your Purchases, try this User Tip:

Get iPhoto 9.6.1 if you didn't update before OS... | Apple Support Communities

The main idea is to move the iPhoto app to the Trash, so Spotlight does not see it as installed, reload the AppStore, and then to try to download again from the App Store - from your Purchases tab, not from the main page, since you can neither buy iPhoto nor update it, but you can reinstall, if your AppleID is associated with it.

Apple stopped selling iPhoto from the AppStore. And that makes updating more difficult. The easiest way to update is to move the incompatible version to the Trash (don't empty the Trash) and then to download again from the Purchases tab of the App Store.

So, do you see iPhoto on the Purchases tab of the AppStore, when you sign into the AppStore with your old AppleID?

You're welcome 🙂