Diplomacy: Can't cancel a resource deal?

[ageddyn]

I had a luxury resource deal with the AI... and now that I'm about to acquire that resource, I'd like to cancel the deal..... umm where is that cancel deal button?

 

[Shillen]

I had a luxury resource deal with the AI... and now that I'm about to acquire that resource, I'd like to cancel the deal..... umm where is that cancel deal button?

They automatically end after 30 turns.

 

[MasterDinadan]

The only way to end the deal prematurely is to go to war.