I was going to have a minimum KIX/ITM transfer in April but somehow "thankfully" my inbound flight was delayed for an hour. The domestic ticketing counter at KIX helped me get rebooked from ITM-HND to KIX-HND. So problem solved and I could sit down and have lunch instead of desperately trying to get to the other side of Osaka.
Concurring with SilverChris, if any hiccough happens definitely get it sorted before you leave NRT. I don't know if the OP has an ANA-issued ticket and you would be rebooked automatically. Mine was a UA-issued ticket so I had to go to the ticketing counter and explain the situation, and the counter really appreciated that I had the itinerary printed out.