Specifically the feat Versatile Channeller
Prerequisites: Channel energy class feature, necromancer or neutrally aligned cleric (see below)...
.... [editted description of what feat does]
Note: This feat only applies to necromancers, neutral clerics who worship neutral deities, or neutral clerics who do not worship a deity -- characters who have the channel energy class ability and have to make a choice to channel positive or negative energy at 1st level. Clerics whose alignment or deity makes this choice for them cannot select this feat.
If a previously neutrally aligned cleric became evil would they still be able to use it? (They do not worship a diety so they will not lose channelling, spells or any other abilities).
As usual RAW answers and I understand a lot of people dont play strict alignments