Do characters lose feats if they lose the pre-reqs

Question

Specifically the feat Versatile Channeller

Versatile Channeler

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.

Versatile Channeler

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

Answer 1

As from the RAW you don't "lose" a feat. It is "just" unusable if its prerequisites are no longer fulfilled, until they are fulfilled again.

If as a GM you find this too harmful -- for example for alignment changes -- you COULD rule that he loses the feat and can choose a different one instead, but as far as RAW is concerned he has the feat and just can't use it.

Now to this special feat: http://www.d20pfsrd.com/feats/general-feats/versatile-channeler states:

Prerequisites: Channel energy class feature, necromancer or neutrally aligned cleric (see below).

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.

This means even if he has the channel energy class feature the feat is inactive if he is not a necromancer OR not a neutral cleric who worships a neutral deity OR no neutral cleric who worships no deity at all. Thus if he is no necromancer he needs to be neutral and either serve a neutral deity or no deity at all. The feat is unbuyable if he doesn't have it already (or is just plain inactive by RAW if he has it and changes alignment to non neutral as a non necromancer).