Porter Airlines generally requires that any changes to baggage after check-in be addressed before the passenger proceeds to the security checkpoint. Typically, once a passenger has checked in and their baggage is tagged, they may not be able to alter their checked baggage requirements. However, there may be some options available at the time of check-in, such as adding additional baggage or upgrading the baggage allowance, subject to the airline's policies and availability. It is advisable for passengers to carefully review their baggage allowance and plan accordingly prior to checking in. For specific information regarding baggage policies and any potential changes after check-in, passengers may want to look at the current information available on the Porter Airlines website, which provides detailed guidance on baggage regulations and procedures.