Hi!
Whilst I can't say with complete certainty, the outcome will probably depend on what you want to do next. If you're hoping to unsubmit the application but not reapply in this cycle, it may be best to simply leave it as it is (as it won't affect any future applications you make). Alternatively, you could politely contact the graduate recruitment team and ask whether they can withdraw it from their end.
If the intention is to unsubmit and then resubmit a new application in the same cycle, this is less likely to be permitted. Many firms don't allow candidates to reapply within the same recruitment round once an application has been submitted, and they may not be comfortable accepting a second submission, as you would have technically already applied in that cycle.
I'd say the safest approach is to email the graduate recruitment team, explain the situation, and see what they can do - they'll be able to give you the most definitive answer!
