Here are some tips for when your flight plans go seriously sideways.

Recently, my friend and her sweetheart got caught in Paris during the global Crowdstrike meltdown. Panic-stricken, she called me for advice. They were flying Delta, heading home, until suddenly, well, they weren’t.

I suggested they embrace their unexpected stay in the City of Lights—there are worse things than being stuck in Paris!—especially as they’d ultimately get a chunk of their expenses reimbursed. Four days of French cuisine, museum wanderings, and boutique shopping later, Delta and Air France finally found them a way home.

I’ve since helped her sort out refunds for canceled flights and expenses. (Don’t ask how much time she’s spent on hold.) During the process, here are some of the key lessons she learned about what to do when a flight is canceled or significantly delayed amid major travel upheaval:

Skip the Line, Hit the Phone (and Lounge). Forget those mile-long customer service queues. Call the airline immediately. If you’ve got lounge access, head there for comfier surroundings and on-site help. My friend’s call to Delta took six hours to get returned, but at least they had free snacks while Air France agents worked their magic.

Travel Insurance: It’s Not Just for Doomsday Preppers. Always book with a credit card offering travel insurance. But read the fine print! My friend’s card promised to cover reasonable expenses—but only those charged to that specific card. Hence my advice to put their Paris hotel on that plastic.

Pack Like Your Luggage is Going on Vacation Without You. Because sometimes, it does. My friend’s partner learned this the hard way when he impulsively checked his carry-on. Always keep a change of clothes, meds, and toiletries in your carry-on.

Receipt Hoarding: Your New Hobby. My friend and her guy had to buy essentials when separated from their luggage. Delta offered $50 per person per day for delayed baggage, but proof of purchase was key. Save. Those. Receipts.

Screenshots: Your New Best Friend. When Paris hotels were booking up faster than croissants disappear at breakfast, the only available airport hotel showed a rate of $12,000 per night. Likely a glitch, but I took a screenshot. It might help justify the $460/night boutique hotel they ended up booking in the city center.

Airline Apps: Not Just for Boarding Passes. Download your airline’s app and check it religiously. It saved my friends a wasted trip to the airport when their rebooking changed without notice.

Zen and the Art of Airport Patience. Remember, those frazzled customer service agents aren’t controlling the chaos any more than you are. My friend witnessed an irate couple nearly get arrested for their meltdown. Guess who probably didn’t get any special treatment?

The Squeaky (but Polite) Wheel Gets the Upgrade. Don’t be afraid to ask for better options, nicely. My friends turned coach class middle seats into premium economy and aisle seats just by explaining their situation calmly.

Know Your Rights (It’s Not Just a Catchy Phrase). Familiarize yourself with both U.S. Department of Transportation rules and EU regulations (if applicable). You might be entitled to more compensation than you think.

Negotiate Like a Pro. If the airline’s offer seems low, don’t be afraid to push back. A little persistence can go a long way in getting fair compensation.

When Life Gives You Lemons, Make French Lemonade. The first evening of their (unexpected) stay, my friends decided to stop stressing and enjoy their bonus time in the City of Light. Sometimes, the best travel moments are the unplanned ones. C’est la vie!

Twist’s Take: These suggestions may help if you are facing a prolonged change of flight plans.