Confirming a Gig means the Pro is committing to working the Gig and being on time for the start of the Gig. If a Pro is late to a Gig, even if the Pro messages the business via the in-app chat feature that they are “running late” or “on the way”, the business has the right to send the Pro away and not allow the Pro to work.
If a Pro is late to a Gig and the business sends the Pro away, whatever dismissal category (Call Out, No Call No Show) the business files the dismissal under will stand, and whatever penalties associated with that category will be enforced.