Alert to Betfair in order to change the participants in a market

There is a substitution in Skills Challenge in the All Star 2010, and one of the listed players in the Betfair market do not take any part, and all the bets will be void.
How can I alert to Betfair in order to change the participants in that market?

Westbrook to replace Rose in Skills Challenge.

http://www.nba.com/2010/allstar/2010/02/13/rose/index.html