If you want recurring appointments to be only for a limited amount of time, you can "set" an end date for your recurring appointments by doing the following:
Go to your GoReminders calendar.
Locate the appointment AFTER the last appointment you want to keep in a recurring series.
Click the three dots on the appointment.
Click the Delete button.
Select the radio button for, "Delete this appointment and all appointments after it in this series."
Click the green Delete button to finalize removing the extra appointments.