With the details above, you typically will get a better deal if you move the flight, if it's a straight forward and unchanged reservation then the cost of this may be visible online if you start the change options. You can use the Finnair website to generate an e-ticket email which will help since it will show the fare basis, and if you have a tool such as ExpertFlyer to see the conditions. Or try the Chat Bot, Twitter DM or the Facebook equivalent.