Not sure if this is the right answer, but if your reservation says "Entry Point: Mt. Whitney Trail (Overnight)" then you should be able to pull up the reservation on recreation.gov, click "Modify", then select "Mt. Whitney Trail - JM35" from the drop down menu under "Exit Point". "Baker and Green Lakes (Exit Only) - JM22" is the first option on the (alphabetial) drop down menu so perhaps that was the default when you made the reservation? If someone has better info please chime in! Good luck and have fun!
