Originally Posted by Often1

Make certain that the agent at check-in knows exactly what it is that is needed, that you repeat this with the GA and the FA onboard.

Even when things get messed up, the first communication on arrival is about special requirements such as wheelchairs.

There is also a Resolution Officer on duty, whether physically or by phone, at every airport. If there is even a remote concern that you are not being heeded, simply ask for the Resolution Officer. That person has the authority to direct any specific service required or otherwise available and can even message a connection point.