If you want/must/need to change a flight, contact the airline. They (Delta) changed my flight with no fee, but I tried to 1) be nice 2) request as minimum of a change as I could) 3) be prepared to pay if I had to 4) use CDC published levels and recommendations as a reason for requesting the change 5) be nice.

You can also contact airline ticket counters in cities and airports. Rumor has it that ‘being nice’ is still a wise approach. Ticket agents have a lot of rules and some ability to bend them. Being mean or demanding often isn’t a good approach when you need their help. YMMV

Airlines and airline call centers are very busy right now. Be prepared to wait or ask for a callback. While call centers are being overwhelmed, flights I’ve been on are often not full. The flight from Bangkok to Tokyo I was on had many, many empty seats. (Yes, I am generalizing from minimum data here, but airlines may have half-full flights they can change you to with little disruption.)

Your travel agent or booking company may also be able to help if you tell them what you need, but be specific with what you want to change and how. Also, it can be hard to communicate with spotty connections and many hour time differences.Do not wait until the last minute to try and change an itinerary. Call if you can on their time.

Your credit card company may also be able to help, especially Platinum American Express or any other card with concierge services.Big hotels with concierges can help as well, especially with local medical help. Capital cities also will have US embassies you can contact. If you want to play doctor, most SE Asian pharmacies will sell you most things you can name and you can at least ask for them. They can often recommend local medical help. If you want to see a doctor, an emergency room visit with a prescription in Bangkok cost my friend $60 USD. (I can’t remember if that included the taxi ride to and from or not.) Asians are not very concerned about medical privacy, so be prepared to be asked questions (triaged) in public before you see a doctor.

Most airlines and/or airports in SE Asia are performing temperature checks when you board an airplane and after you disembark. Many shopping centers are as well. If you have a fever, it’s going to be a very tough game. Most/many/some SE Asian countries are offering help (diagnostic and treatment?) if you already have corona virus’s symptoms. If you don’t have evacuation insurance, I’d try to get to a major city in a country with good medical facilities (Thailand or Singapore) as the first fallback. Second fallback, get to the largest city you can. If you’re on a tour, the tour guide is your first resource.

Yes, I am not a travel agent or medical doctor, nor do I play either on TV, but I did recently change my travel plans to avoid a 5-day stopover in Tokyo and fly as directly as possible from Bangkok to Minneapolis, and I’ve been in four SE Asian countries in January through March, and changed planes in Seoul and Tokyo airports.