Flight from Tokyo to Munich was randomly cancelled

Hallo everybody,

I just recieved an e-mail that my flight from Tokyo to Munich on the 31.12.2026 was canceled. I got rebooked on a connection flight on the 30.12.2026 over Frankfurt.

I can not logisticaly do the Frankfurt flight, my only option is getting rebooked on the ANA flight on the 31.12 or go with LH on the 01.01.

What are my realisitc options? Do i need to pay a price differnce? Something like this never happened to me so before I do anything I would like to know what the best options are for me.

EDIT/UPDATE:

I had the choice to rebook both flights over the LH site, because I booked the full flight in Buisness Class over their Website.

I then took the return flight on the 01.01 with LH. ANA/NH was also listed but only for the 30.12 and 01.01. Very weird that I first got rebooked on the 30.12 over Frankfurt, why?

All flights were listed as 0€ rebooking flights in the same booking class.

E-Ticket got issued but I still haven't gotten a confirmation E-Mail. Should I be worried the system fucked up or am I save the moment I got a fully new E-Ticket issued?

Also why did LH suddenly cancel that flight only? Seems that also the Frankfurt return flights from Haneda on the 31.12 are all canceled, due to New Years Eve?