Ok this is really simple as long as you know where your MMFApplications folder is.
By default it should be located under username/appdata/roaming/MMFApplications.

I have not tried this with the game running but editing the file without the game running and then starting it definitely works.

Open the FNAF6 file with Notepad. You will see the code lines
night=# (whatever night you are on)
phase=1 (the daytime phase of the game)

Simply change phase to equal 3, then save the file, close it and start the game. Choose to continue and you are finished with the office phase and immediately at the Salvage phase.

Note:
phase=1 Daytime in the Pizzeria
phase=2 Begin at the office phase at night
phase=3 Begin at the salvage phase of the night
phase=4 Begin at the screen tallying up your numbers after the salvage

Thanks for reading. I hope someone finds this useful.