Here it is (from FAQ)
What happens after I've chosen the winner or runner up winner(s)?
After choosing your winning entry, both of you enter the Contest Handover. It's a short process in which you and the freelancer agree to transfer ownership of the entry from them to you. Once it's over, you will be the owner of the entry and the freelancer will receive their prize money!
Same process after selecting the runner up winner(s). After buying an entry, both you and the freelancer enter the Contest Handover. Once Handover is done, you will be the owner of the entry and the freelancer will receive their payment.
Can I ask for changes to the entry(ies) I’ve chosen?
Yes, you can ask Freelancers for revisions by private message or during the Contest Handover.
Note: We recommend that freelancers try and accommodate minor revisions but anything else is up to them.
Hello. It is impossible for me as a designer to post a new design, because submitting is over for your competition. Only legal way is that you select winner and than in handover stage i send you files you need. You, as an employer, are protected from any fraud. After i send you files, you will release reward ONLY if you satisfied with my design, That is the way how this site is working. If you want i can send you more than one file. In handover stage we can do some more modifications on selected design. I hope you'll understand this. Any other way for sending you a design is illegal (for freelancer.com) You can confirm this in HELP link and find how contests works.