I came across the article for editing Attendees Lists Solved: Re: Attendee List Cleanup - SAP Concur Community

I've noticed we have multiples of many employees, and also employees entered in as business guests. My question is if I clean up the attendees list, will this change past reports or reports in progress? 

Also, can we have an attendees list of all employees, even ones not users in Concur? I'd like to turn off the ability to add an employee, but can't do that if it's only for users (though don't think it will help completely since they're adding employees as business guests). 

Thank you,

Alicia