To most women, summer fashion is about sundresses and the triumphant shedding of sartorial encumbrance. But for women in pedestrian-friendly New York, summer actually means a certain bulking up of the load — with an extra pair of shoes. The scantily-clad season is especially conducive to showing off one’s Chloe wooden platform wedges. But sticky weather can wreak blistery havoc on the pedicure, comfort, and even physical safety of anybody for whom sky-high strappy wedges are more than a well-chosen luxury — they’re a necessity.

Although plenty of stylish working women remain slaves to vanity, plenty of others have decided to buck convention: For the road, they don a pair of lightweight walking shoes like ballet flats or flip flops. New Yorkers may choose the trendy and sturdy Havaianas or cheapies from Old Navy — but emphatically not the “Working Girl”–era white sneakers favored in Chicago and Washington. They then change into stilettos or platforms for their destination, whether business meeting, dinner, or after-hours soiree.

Problem solved? Not quite. For once one has decided to undertake the shoe swap, there arises etiquette issues of where and how to do it.

The key, at least for the women polled for this story, is not the quantity of people who see you in flip flops versus stilettos but the quality. Business associates or important social acquaintances should only see the shoes meant for your outfit, these women say. (If being photographed for the society pages is a primary objective, one should never even consider alternative footwear.)

“I once forgot to put my grown-up shoes in my bag and, let me tell you, it’s not good conducting a sales meeting in flip flops,” an account manager at Architectural Digest, Wendy Landau, said.”Let’s just say I hope I never make the same mistake again.”

Among the city’s choicest shoe-swap spots are the subway and any conveniently located stoop.

“On several occasions when I couldn’t get a seat on the subway, I’ve relied on the kindness of strangers to hold me up while I change into my Pradas,” a gallery director, Jenny Liu, said.”That said, you really shouldn’t endanger your fellow subway riders. For pete’s sake, even if the subway is lurching, control your stilettos or platform wedges so they’re not skewering or bashing some poor innocent straphanger.”

Other favored spontaneous changing rooms include Starbucks, well-placed benches, and the gym.

The shoe-swap itself should be as quick and covert as Superman in the telephone booth. Heaven forbid if anybody but a complete stranger sees the actual shoe change.

“I try not to change in front of very proper elderly women, as they sometimes look askance,” Ms. Liu, who describes her shoes as “tall, glorious, and costly,” said. (Perhaps woman of earlier generations should be forgiven their distaste; after all, they managed month-long European sightseeing tours in nothing but pumps.)

Opinions are more mixed on being caught in the act by doormen and elevator operators.

“My idea of bliss is being put into an empty private elevator, with seat and mirror, and making a very elegant quick change, always smiling at any obvious security cameras and keeping my foot pointed downward to maximize slimness,” the head of couture auctions at Doyle New York, Clair Watson, said. Her work often takes her to residences on Park and Fifth avenues. “Frankly, I do exactly the same if there is an elevator operator. The first time I garbled something about hellish heels, but I soon realized that those guys have seen everything and are the soles, ha ha, of discretion.”