Credits:

YeahPotato

How To

NOTE: You will need to add a check for flag 0xXXXX in the whiteout scripts and if it's set, load the player's party and then clear the flag. This is necessary to load the player’s full party again in the event that they whiteout!

Whiteout Script Here (Guide 8.4)

Use the following script to initiate the battle:

section0:
  lock
  faceplayer
  if.flag.clear.goto 0xYYYY <section3>
  
section1:
  msgbox.npc <auto>
{
That was a great battle!
}

section2:
  release
  end

section3:
  msgbox.default <auto>
{
Lets battle!
}
  special SavePlayerParty 
  special ChooseHalfPartyForBattle
  waitstate
  if.no.goto <section2>
  special ReducePlayerPartyToThree
  setflag 0xXXXX
  single.battle.nointro [trainer] <auto>
{
You win!
}
  special LoadPlayerParty
  setflag 0xYYYY
  clearflag 0xXXXX
  goto <section1>

Happy Hacking!