You are in South Florida. I would suggest repotting now as Spring is starting. Find some small/medium bark. Soak it for a few hours to take up water. Add a little sphag moss to the mix and repot the plant. If you can put your plant outside, all the better. As the above poster asked, make sure the pot has drain holes. Orchids do not like wet conditions. They like air movement. Your plant might have some fungal issues going on now so repotting is important. You can remove the yellowing leaf. Your plant will start its growing cycle and grow new leaves. I'm in Sarasota and all my Phals are outside facing East. They love that exposure and are all blooming or spiking now. Please read about your plant it will help you along the way. How to grow Phals Jane

Any sticky reside (honeydew) on lower leaves or the floor? Do you know how to test for spider mites? What are you fertilizing with? How long have you had it, and, have you ever done a full repot, and what kind of soil is it in. In order for new leaves to form normally, Ca(lcium) must be in the nutrient stream at all times. If the plant is not taking up enough Ca, or the flow of the nutrient stream is disrupted, new leaves emerge deformed, often with brown margins which turn necrotic with the necrosis extending inward. Your plant presents classic symptoms. The question is, is the deficiency caused by an actual deficiency where there is not enough Ca in the soil, or, is a cultural influence (over-watering, soil compaction, an excessive amount of Mg (magnesium) in the soil, a pH issue, ....? Low light, cool temperatures, high humidity also slow respiration which slows the nutrient stream which limits Ca availability which exacerbates manifestations of the deficiency - the malformed leaves. You don't offer enough info so I can't say what caused it to occur, but look first to over-watering. Going only by the odds, that's the probable cause. Al

It’s in a drainage pot inside the ceramic pot, it’s not been watered for about 2 weeks! I thought over watering too but I’ve only watered it twice since buying it in mid December! it could be cold As the house gets quite cold in the day? I’m just wondering if it’s salvagable? I’ve cut off the rotting bit and am hoping it helps 🤷🏼‍♀️

chamaegardener..what an adorable Fire Island 💕..I have Fire Islands in 3 locations..here's a glimpse of one in this pic I took today.. Fire Island looks good with creeping jenny.. debra..yay!..your hosta are up!..