How do I recover a family members account to sign them out of a device?

Can you ask your daughter to do that? If she has forgotten her information, this document tells you the various ways you can try to discover your forgotten Apple ID --> If you forgot your Apple ID email address or phone number - Apple Support Note that typically this is an email address you use.

This document outlines what to do If you forgot your Apple ID password --> If you forgot your Apple ID password - Apple Support

or go directly to this link --> http://iforgot.apple.com/

If you still need help:

Contact Apple for help with Apple ID account security "This article provides country-specific Apple Support contact information for customers seeking help with their Apple ID password or other security-related issues." Click here --> Contact Apple for help with Apple ID account security - Apple Support

If all you care about is access to the device and do not mind it being wiped, Apple can completely reset a device if a person can provide sufficient evidence of valid ownership. Do this online at: Activation Lock support request - https://al-support.apple.com/#/additional-support Apple says, "Proof of ownership documentation is required," but does not detail what currently constitutes proof. Prior to this new online service Apple typically required the original receipt issued by Apple or an Apple Authorized Reseller and documented provenance (so typically it would be the original owner who does this, or a descendant with legal proof of ownership). This will give you access to the device but won't restore access to the account used to lock it.

Apple recommends you "Keep your receipt after you buy an Apple device" --> Keep your receipt after you buy an Apple device - Apple Support