Most likely your Feb 16 flight is confirmed, or it should not be ticketed.

Your ticket should be the type that is good for six months or more, but you should check with your TA or CX. The ticket validity should also be on the e-ticket receipt. Most ex-US tickets allow change on flight segments except the first one or if it is a promotion for certain flights only. Hopefully your ticket can be changed if seats for your booking class is available for the new flight. However, your change is probably not free because you are changing from a weekday flight to a weekend flight.