I have read the forum entry at https://forum.sambapos.com/t/change-ticket-type-not-working-consistently-or-as-expected/12606 but it is long ago and maybe there is some new trick.
I am also doing refund and functionally it works perfectly. I need a separate ticket to comply with the local laws here in the Philippines - it is complicated.
The flow is first select a ticket and display it. Then I fire a command which clones the ticket and changes the ticket type to “Refund Ticket”.
Well I thought that this change of type might go against the old ticket but it does actually work against the new one but just a little bit too late 
…
So I chained another command and this is my observation:
I intercepted the “order added” event and within the rule the ticket type was still the old one.
The same is true for the “Ticket Displayed” event - {TICKET TYPE} still claims to be the old one and that’s how the visibility rules of the buttons are determined - a new ticket with the old type look.
Finally my chained command gets invoked and here the system changes its mind and tells me that this is now really a refund ticket. I give everything in this rule - save the ticket and load it using the UID but it does not help/work. The rude method of closing and opening works but this flickers. Actually when there is an entity involved in the ticket then the result is as expected and the ticket screen behaves like a Refund Ticket screen … maybe somebody knows something more elegant than close/reopen.
Anyhow this is not too big of an issue as I don’t expect many refunds - first you have to ensure that you don’t perform premature payments and second you won’t usually allow customers in a restaurant to bring back what they consumed … and so I am fine when I am the only one who has to navigate through my messy refund flow.