Currently there is no built in option within the UI. However, this is possible to pull using our REST API. You'll want to send a GET request to https://api.demdex.com/v1/users/ with your bearer token, and this should provide a list of all your AAM users in a format that can be converted to CSV fairly easy.
Another alternative is to open a ticket with our support team, and we can pull a CSV from some DB queries. If going this route, please provide any of the following when opening a ticket: AAM subdomain, partner ID (PID), IMS org ID.