Yes. A JPEG can still be edited in most photo editors, even though it has less flexibility than a RAW file. To reduce an overly warm look, open the image in your editor and adjust white balance or use tools such as color balance, saturation, and curves until the color looks more natural. There’s nothing special you must do just because it’s a JPEG—the main limitation is simply that JPEG usually gives you less room for extreme correction than RAW.