I'm afraid the prospects aren't very good if it is crown rot. You can trim off all affected parts, making sure to sterilize the instrument every time you hit infected tissue (which will not be white/clear). cinnamon, sulfur, or a myriad of commercial products on the wound. And hope for a basal keiki. There are hormones for sale to induce keiki formation, but unless it's a unique plant or something that otherwise has sentimental value, I'd pass on it. If the plant is healthy enough, i.e. the rot has not spread to the roots and can be contained, it should sprout a keiki on its own. Needless to say, it's a long road back if it should get that far.
My advice is to get another plant, and to make sure you have enough air circulation. And of course never to let any amount of water sit in the crown or axils of a phal.