https://customerservice.fwctc.com/cgi-b ... agung_info
The link above is to the rules governing ticket swap through their web site and at the stadiums, this i beleive is a good route if you buy from a tout. It states you can turn up at the stadium the day before and not on a match day and tranfer the ownership of the ticket. You can also do this by proxy, e.g. if you have a letter of consent, and some form of proof that the ticket was leagally obtained and you never paid more than face value.
By the way if you sell your spares back to fifa you get your money back, but if you buy a returned ticket they charge an extra 15%. Talk about bloody double standards on touting tickets, regardless of the admin cost its a money making exorcise because they know they have sold cheaply and given away too many tickets for free to make a profit from sales. I am sure you would have visited this site anyway looking for tickets and swaps but just in case.