Just show up to the next shuttle! Call groome and let them know your flight was delayed and they will put you in the next available shuttle.
Some people cannot call as they don't have a mobile service. Just go to the pick up point as they have multiple services and one of the other drivers can put a call in to the office for you.
Call Groome to verify if there is room on the next or earlier shuttle.
Groome has shuttles each hour, so if you miss one bus there is another you can catch within the hour.
See if you can take a later groome shuttle or just go ahead and go and kill time in the airport until your flight.
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