Originally Posted by CPH-Flyer

The change policy does indeed seem to be very general, and does not contain any information about your specific booking. If you can look up your booking on the ANA website you should be able to see the specific rules. If you have the ANA reservation number or the ticket number you can check on the site. Alternatively if you can give the booking class (not class of travel) it is possible to find the specific rules.
Generally ANA is correct, it is the travel agency that sold you the ticket that should assist with the rebooking.