You can check if this option is available by going to the button "Manage order" in the confirmation email. 

Select "Change Name". Enter the email address of the new ticket holder. 

Pay the transaction (the name change will be done once the order is completed/paid). 

You will be taken to a new "My Order" page and you will see that the ticket has been sent to the new ticket holder. Select "Confirm" to complete the name change.

Please note that the new order will remain in the name of the primary purchaser of the original order. The name change is also paid for by the original order buyer.