You need to get a separate permit for the additional hiker. You have to get it online--there are no walk-in permits available this year. Here's how you get the permit:
Starting today, keep checking the Recreation.gov
site (set entry point to Mt. Whitney Day Use, and Group size=1). Permits DO show up online
, as people picking up their permits drop off slots due to hikers backing out. Most permits will show up Sunday for the Monday hike, but some will also show up on Saturday. (If people go online earlier and cancel or drop slots on rec.gov, those will show up earlier.)
When you find the slot, reserve and pay for it. The software is supposed to let you update your existing permit and add a slot (only when one is available). If it allows it, you shouldn't need to pay the additional $10 for a new reservation. Otherwise you might need to create a separate/new reservation, with the additional fee.
If it's a new res, I'm not sure if the system will let you pick up a permit for same day as your other one (I think it should
). If not, have another person in your group check for and reserve the permit. Whoever gets it has to pick it up (showing ID) at the Visitor Center, S of Lone Pine.
Not only will 1 hiker be turned around, your whole group will and the trip leader will be fined and most likely banned from applying for a future Whitney permit and maybe other destinations.
Whoah!! Not sure where you get your info, but I can't imagine a whole group being turned back. The group leader and six hikers would all be legal. It would only be the un-tagged non-permitted hiker who would get fined. And nobody goes about banning people from the trail.