removing email from apple Id that is no longer active
Years ago at the start of all the apple things, we created our apple IDs for each child, as well as my personal one. Somehow those were all linked (prior to family share). Back in the day we were able to disconnect the link between our daughters phone and mine, however her ancient email remains as the apple ID default. We have no way to delete this email, as we weren't tech savvy enough to set a secondary email, so we can't reset the password to log into the account. My question is, is there any way at all to remove this email as an apple ID. We are in the process of now finally establishing our own IDs (the third one is still liked through purchases) but it's time to cut the apron strings from the adult children. Thank you for any help.
Windows, Windows 10