To stay up all night long to make sure that your are on time for the start of an early morning appointment.
'Pro Nighters' are often insomniacs, or extremely dedicated, or the important event's start time drastically conflicts with a normal sleep cycle.
Pulling a 'pro-nighter' is usually saved for important events such as job interviews, sales meetings, or court; or any event where the long term consequences of being late are far more painful than the short term discomfort of not sleeping.
An "All-Nighter" and a Pro-Nighter" are similar but differ by the priorities of the START and END times of the sleep affecting activities to be performed.
A Pro-Nighter ignores sleep to START an important early morning activity. Whereas the All-Nighter starts an activity and continues it on through to the END without sleep.
"I have to wake up on time and cannot miss that morning meeting. I am going to pull a 'pro-nighter' and make sure I am there on time."
"He has to be a 'pro-nighter'! If he is here at work this early he hasn't gone to bed yet."