@nowachance If your company has enabled the feature, you should be able to put the reservation On Hold. When you get to one of the last screens during the reservation, you will see a button to Hold the reservation. It will hold it for at least 24 hours. Keep in mind that the selected airfare could no longer be available if you put the trip on hold.
If your company has not enabled the Hold option, what can happen if you navigate away from any reservation screen after selecting your flight option, you will see an Unfinished reservation link in the Alerts section of the SAP Concur home screen. You can click the link to finish the reservation, but this is not the same as putting it on Hold.
I hope this helps. Let me know if you have any other questions.