Is it possible to use practice field in finals or qualifying match? Because i couldn’t find any rule that mention about it.
Are you asking if an Event Partner can use a field that was used for practice for skills, qualifications, or elimination matches? I do not see why not, if the field is to spec, there is no reason not to. The only issue would be assuring it had the same competition field controllers, monitors, and equipment identical to the other fields used in the tournament.
Unless I missing something in the question.