Once you have lost the crown of a Phal from crown rot, the chances of saving the plant are close to zero. In a home environment with less that perfect growing conditions, even if you do by some chance get a basal growth from below the rotted crown, it may take several years for the plant to grow to blooming size again.
Use this loss as a valuable lesson in orchid culture, toss the plant and buy another one to enjoy now. To preclude this happening again, do not allow water to sit in the crown for a protracted length of time.
Good luck,
CL