The bayed leopard hunt comes to an end when the cat is shot, and pulling out of that commitment is generally not possible.
However, a treed leopard can be passed on in most cases.
I find roughly an even split between treed and bayed outcomes.
As the leopard does not present any obvious visual trophy markers like horns, antlers, or ivory, it is almost impossible to gauge specific trophy characteristics accurately while in a tree.
The parameters of passing on a treed cat would need to be agreed on pre safari.