This means the reallocation facility is not available and you can no longer transfer your tickets into another person's name. For most events you can reallocate tickets up until midnight on the day before the event (or midnight on Thursday for events between Friday and Sunday).
In some cases the event organiser, venue, or sometimes the artist themselves, has specifically requested the reallocation function be turned off. The reason for this could be that the event is high profile, secret or a fan club show.
In this situation the person who originally bought the tickets must attend the event themselves together with all other members of the party. We're unable to make exceptions, so please ensure you can attend before buying tickets where there is 'no reallocation'.