User code already in use?

Family of three here. I am the Owner and have a code. My wife and daughter are shared users. I originally added daughter as a guest and gave her her code from our previous alarm system. I deleted the guest account because she couldn’t use the app. When setting her up as a shared account, I can’t give her the desired code because the system says the code is already in use even though the guest account was deleted. Any ideas how to work around this? Thanks.