Peace -

Cuckoos are nice little birds, but not too bright.

If you just walk past at about 01:45 and cuckoo twice, at 02:00 the cuckoo will think that 02:00 has already come and passed, so if the cuckoo has minimal cleverness (normal for cuckoos) it should automatically/reflexively cuckoo three times, and will remain on the adjusted time schedule thereafter.

It's much more difficult when the change is in the other direction, since you must prevent the cuckoo from hearing one time, so that it will repeat the same number of cucks at the following hour.

If this doesn't work, I can assure you that the only reason would be that instead of an accurate "cuckoo" you must have "dodo'd" and should look for the mess and clean it up.

John