I have a friend in the same type of situation. Has a OW ticket with 6 stops in Europe. Agents were unable to get an Eticket out of the Venice leg, so the whole thing is a paper ticket.
Problem is, we want to change the date on one of the legs, once availability opens up.

So while we can change the OW ticket for free (same for AAdvantage Award), there will be a $15 fee, and an airport visit to get the ticket reissued. I don't think it is a big deal, but you may.

Val

Also note that tickets issued at the airport are subject to a $15 USD fee.



EDIT: I missed the part where he was changing carriers. My info only applies to a date change involving a paper ticket on an award.