Hi, the party that occurs when you finish a film or television series is usually called a 'wrap party'. It's where cast and crew celebrate the completion of a production. Cheers, Luke

In English we say "What do you call...?" not "How do you call...?" in this context.

I've only heard of "cast party".

I think that is a "wrap party" a wrap is what they traditionally say when filming is complete the actors are no longer needed and the film goes onto/into the next production stage of "post production" A "top out party "is the same at a similar stage for large construction works to large buildings. The top of the building has been built and all that needs to be done is the minor things "the finishing". The workers who got the building to the top, now go elsewhere their skills are no longer need other skilled craftsman/women take over the "finishing".