Here is an example of how Hollywood (sometimes) works:
In 1997, the film "Air Force One" was released. About 4 weeks before the release date, "someone" decided that the (already completed & recorded) score sucked, and needed to be totally removed and replaced. This meant hiring a New Composer ( "...get Jerry Goldsmith on the phone!!!"), an army of "Orchestrators" & Copyists, contracting an orchestra, booking studio time, etc. My "orchestrator" friend was one of the "army", and, (working 'round the clock!), they DID compose/arrange, copy, record, and replace the WHOLE Music score in time for the release. As each new cue was completed, it was sent to the copyists, and then to the studio for recording.
There is NO Busine$$ like Show Busine$$.
Thanks.