AFAIK there can be only one preConditions tag at the beggining of the changeSet. Your scenario is not supported. Workaround would be to divide this into two changeSets.
There will be two preconditions, the first in tne update changeSet, and the second in the Delete changeSet. And if I execute these changeSets in a MasterChangeSet, I saw in another topic of this forum that it’s gonna first look for preconditions in all the changeSets, then execute the first changeSet.
My problème is : I want to execute the first changeSet before the precondition in the second one.