In today’s Azure Quick Tip, we are going over the process to resend an invitation to a guest user in Azure Active Directory. When looking at the properties of an Azure guest user, we have two pieces of information that can shed some light on how the process is for an external user. The first one is the Source, and if the status shows as an Invited user, that means that the external user hasn’t completed the enrollment.
Reference:http://techgenix.com/resend-invitation-active-directory-guest-user/