Hello @Richard Morgan, welcome to the Box Community!
We’re still checking if this functionality is possible with Box Relay and awaiting our internal team’s response.
In the meantime, here are some related articles regarding Box Relay:
We appreciate your patience, and we'll get back to you once we hear from our support team. 
Thank you ma’am, I appreciate you looking into it for me.
You’re most welcome, @Richard Morgan, and thank you so much for your patience. 
Regarding your workflow, if the folder is not known in advance, it may not be possible with Box Relay at the moment. The trigger would have to be Files with metadata, and the outcome would be: Folder Move. The only folder you could select would either come from the context of the workflow (folders created in previous steps) or an existing folder (a static pick from Box).
We are planning to support a few variables more in the future, and we’ll be sure to provide updates in our community.
In the meantime, if you need further assistance with Relay or a strategic approach for your organization, please feel free to reach out to your Customer Success Manager.
Have a great day ahead! 
I really appreciate you looking at it, and i understand why it doesnt work now.
maybe you can help me figure out another solution. is there a way to trigger a folder action based on who it is shared with? Say that i have closed a case and share it with the supervisor specifically, i would like it to be moved to the complete folder based on adding the supervisor as a collaborator.
Hi @Richard Morgan, you might want to consider this Relay trigger:
Folder events > Add Collaborator > Select a folder (e.g., the "Complete" folder) where the triggered folder resides or to which it will be moved or copied.
Please let me know if this workflow achieves the desired outcome. If not, we'll explore other available options to help automate this process.
Thanks, and have a great day ahead! 