Updates the number of participants for a class or course booking and changes
the totalNumberOfParticipants for the relevant sessions.
You can't update the number of participants for appointment bookings.
You must specify either participantsChoices or totalParticipants.
The call fails if the specified participantsChoices aren't among the
supported service options and variants.
You can only call this method when authenticated as a Wix app or Wix user identity.
There is 1 error with this status code.
This method may also return standard errors. Learn more about standard Wix errors.