First, verify whether your trip is public, private, or custom:
Public Trips = Makes it so bookings can be made until all seats are booked.
Private Trips = The default option. After one booking is made, it is closed off.
Custom = A Listing setting making it only so a certain person or group of people with a Booking Access Link can book the trip.
If your listing is public...
You'll need to adjust the client-to-guide ratio.
Adjust this here
Go to Listings.
Click the Edit Listing button.
Enter Max Seats.
Enter Guide Ratio (seats per guide).
Click Next to save.
For example: If you have 5 Max Seats and your Guide Ratio is 5, you'll have 1 guide assigned for every 5 seats.
If you have 7 Max Seats and your Guide Ratio is still 5, you'll have 2 guides assigned to this listing.
If you only enter a number for Max Seats (e.g. 10) and leave the Guide Ratio space blank, one guide will be assigned regardless of the number of seats (e.g. 1 guide will lead up to 10 people per trip).
If your listing is private...
This is the default option for trips. As soon as a customer makes a booking, regardless of party size, that trip is closed to further bookings.
To allow for more people to book a trip, you'll need to make your trip Public:
Go to Schedule.
Find the listing you want to change to public.
Click the pencil icon.
Check the Public box.
Click Save.
Repeat for all instances you want to make public.
If your listing is custom...
Only customers with the direct booking link can book a trip. Therefore, you'll need to make this public if you want to allow for more seats:
Go to Listings.
Click the Edit Listing icon.
Uncheck the Custom Booking box.
Click Next to save.