How can I change key in the file.apk?

You uploaded an APK or Android App Bundle that is signed with a key that is also used to sign APKs that are delivered to users. Because you are enrolled in Play App Signing, you should sign your APK or Android App Bundle with a new key before you upload it.

When I try to uplkoad the file.apk in google play , gave me this message .. how can find solution ?