Possible to edit Lich class (not template) to allow divine magic prerequisite?

[Forechosen]

Hi everyone, first post here.. so hello

Question is pretty much in the title, but I'm wondering if it would be possible for me to edit the Lich prestige class from:

'must be able to cast at least 6th level arcane spells'

to

'must be able to cast at least 6th level arcane or divine spells'

I'm really hoping this will be just a case of opening the toolset and simply changing an option. But it's been genuinely years since I've used the toolset (although I used to be alright at it) - so I'm at a bit of a loss right now. If anyone could give me any advice on this matter, it would be massively, massively appreciated!

I understand I can add a Lich template to a divine caster, but honestly I'm much, much more interested in levelling up a prestige class one manually.

Thanks for reading!

[rhamnetin]

I know this is a late response, but I'll post the solution for those who come across this thread. You have to edit cls_pres_lich.2da in prc_2das.hak. Element 0's ReqParam1 must be changed to: PRC_AllSpell6