IN MY HUMBLE OPINION, When a large FAN leaf starts yellowing, say it is half yellow, that means in the photosynthesis process, that leaf has ate nutes, sucked in some LIGHT and made food for the plant and buds and NOW, half of that is gone, or used or consumed. Well, what about the other half? Can it not it's energy still be used or consumed?
AND when it is ALL consumed or used, that leaf will naturally just fall off.
Years ago I tried removing lower fan leaves to allow more Light to penetrate in. When i did, the plant went into shock for a day or two, and quit eating or only ate half as much, and just went on "stand by" mode. Then, after a day or two, suddenly, I saw that big fan leaf replaced by a new leaf, and I saw my plant use the energy to replace that leaf, more than it used it to grow bigger and make more buds or bigger buds.
I now believe that removing fan leaves is pointless, and that a leaf has a purpose and will serve that purpose until it is dead. Then it will fall off.