How much would it be to exchange plane tickets to the Philippines?

We have tickets to the Philippines, but we would like to come back a week earlier than it says. How much would it be to exchange them?How much would it be to exchange plane tickets to the Philippines?The best source of information would be the customer service of the airline. Each airline has its own policy and it also depends on the kind of ticket you purchased.How much would it be to exchange plane tickets to the Philippines?try getting a hold of your travel agent.