It depends on the airline that you are traveling on. Typically, each piece should weigh no more than 50 lbs (~23 kg). Do check with your travel airline as some allow up to 2 pieces of check-in luggage plus one carry-on bag.
Most airlines will allow you to change your flight, however flight changes are subject to seat availability. Note that the airline will assess a fee for changes to your original flight. For specific fee information, please contact us prior to your departure and we will advise you of charges as well as alternate flight availability.
Flight refundability depends on the type of ticket you have purchased. The best fares are typically non-refundable once issued, unless you can provide valid proof of your inability to travel, such as a medical emergency.