Solution:
I add a step calling the Method GETRELEASEINFO of BUS2105.
In a condition step I Check the REL_IND value = "2"
Branch to the edition of Purchase Requisition in case of True.
The only issue is that returning structure in Method is a table so I had to add an additional step (Container Step) to get the first (and only) record of the structure, so I can make the condition evaluation.
Thanks everyone !