Say a Human Warlock-6/Mindbender-1 was to gain another level in Warlock and decided to swap out his Charm invocation (required for Mindbender entry) for the Flee the Scene invocation. Is this a legal move, or is it just not allowable? And if it is a legal move, are there any negative ramifications (other than not being able to level up in Mindbender again)?...Such as would I love the Mindbender's telepathy class feature until I qualified for the PrC again, etc?
Similarly, what if you retrained a feat you used to enter a class? Ie. A Human Warlock-5/Chameleon-2 decided to retrain his Able Learner feat (required for Chameleon entry) for Improved Initiative.
Or...An Epic level character getting Epic Leadership, then swapping out Leadership.
Now I know in the case of feat retraining, the PHB2 goes over that not only do you have to meet the requirements when you retrain it, but also must have been able to have taken it at the time when the original feat was chosen...However, I have not come across any resource saying that you cannot retrain a feat if it was the requirement for another feat or a Prestige Class (I found one for PF saying you cannot, but I haven't seen one for 3.5)...Nor do I see anything referring to the similar situation about the invocations. Now I am sure that RAI (and many DM's would rule), that you cannot give up a requirement, but is there any official ruling anywhere?
There has to be some sort of official ruling out there right?...I mean there has to have been plenty of ppl who took/tried to take advantage of feat/skill retraining to get rid of unwanted requirements for feat tree and or PrC's right?