Hi,
I'm not familiar with that SolMan workflow (it's not in my system), and I'm not quite sure I understand your question!
"Could I change this logic (buttons) so the user can reject or accept from the WI, without enter in the order, and modify the current step."
Are you saying that task TS17207930 only contains text (explaining how to manually process a checklist), and you want to automate the steps that it describes?
If yes, then you need to identify the relevant CheckList BOR object (or class) and see which methods it provides for you to use. Also, see which CheckList TS tasks are available for executing those methods.
Then build a new task (based on DECISION.PROCESS) to provide Approve / Reject buttons to the user. Based on their decision, invoke the step to execute the relevant CheckList method
Decision Task --- Outcome: Approved --> Checklist.Approve step
---- Outcome: Rejected --> Checklist.Reject step
good luck!
Paul