With Lufthansa Airlines, though, you won't have to worry about it. Simply contact Lufthansa airline's customer service department, connect to a live agent, and he will complete the procedure for you. Just give him your last name and the confirmation code from your reservations, and he'll take care of the rest. He'll make sure you don't lose anything and get a full refund. He would endeavor to get the balance reimbursed to you as quickly as possible if there is a cancellation charge on your booking.
See at: Lufthansa Cancellation Policy
See also: Aeromexico Cancellation Policy || Emirates Flight Cancellation