Call OTA they said :/
Called expedia this morning, wait time two hours, no thank you, tried twitter no response, finally now got quickly connected later. Expedia was helpful, "ok we will change, that's fine", they tried to change and apparently reservation is "under airline control" I need to call Lufthansa
Oh the wonderful world of airline ticketing
EDIT: finally got hold of Lufthansa and this time they changed it.