HiĀ George!
Thanks for reaching out to us. I’ll be happy to help you with this.
Yes, you can manually create an order for the ticket product and assign it to an already created user. That is all handled by WooCommerce. You can add a new order by navigating to your wp-admin > WooCommerce > Orders > New Order.
If the ticket product is out of stock, then you can manually adjust it by editing the product on the WooCommerce site.
Please note, this is an edge case, so I’d suggest you first test it out, preferably in a dev/staging site, to make sure it works as expected and you don’t disrupt your live site.
I hope that helps. Let me know if any follow up questions.
Best,
Victor