Yes, you have the option of paying a change fee and using the residual value of the ticket in the name of the original passenger. You must inform them that the original passenger will not be flying before the scheduled departure time. Tell them that you do not have the new travel dates yet and that you'd like to leave the itinerary pending while you figure that out and that should work. You'll need the original PNR when the time comes to use the credit so don't lose that.