1. Load your save with the
JS Save Editor. You may have to Save to File, first.
2. Go to Flags and find KASE_TIMER.
3. Find your current time passed in minutes (Days * 1440 + Hours * 60 + Minutes).
4. Input that value. This will tell the game you spoke to Kase just now. He won't leave for another week.
For future reference: The timer doesn't start until you talk to Kase at the bar after turning in the Satellite Hard Drive. You can therefore delay his departure indefinitely.
