Go to the member profile in the Bookings tab

There you will find the recurrent booking associated with this member

Click on the cross on the Recurrent booking

This way, it will bulk delete all the bookings linked to this recurrent booking (instead of having to delete all of them one by one) and stop creating new bookings in the future

You also have the option to send a booking cancellation email to the member to let him know about the cancellation of his recurrent booking