Facebook associated emails

Hello,

I am trying to switch my associated emails for my facebook account. I manage two accounts, one is mine and the other is my daughters. I have three email accounts. I already switched my daughter's FB account from email A to email B. I am now trying to change my FB account from email C to email A, but it says there is already an account associated with this email. However, I can still sign in to my daughter's FB account by using both email A or B. When I sign in to her account using email A, the account settings shows the correct email account B associated with it.
I'm not sure if it is just a delayed change in settings. Do I need to wait for the change? I just need the link between A and my daughter's account to go away, so I can change my account.

Thanks.