BG1&2, NWN1&2, PST (well u can but u lose alot if not all XP) IWD1&2, Morrowind, Oblivion, Skyrim (untill u dont finish skill tree), XCOM, Gothic and countless others. In ME u can't change class u can just change points u invest in different skills - but it doesnt matter in the end cuz u can max almost all. As far as i see complete respec is more of an exception than rule in RPGs.
But yes if like u said there are conditions then its harder to do these test - but not impossible. Saving skill points to invest in these skill chains is in many games very useful and practical but apparently not so much in Deus Ex Human Revolution where i had over 35 praxis left in the end which is more than 50% of all u get :P
I guess there could be a Hammer of Forgetfulness or smt like that and if someone hit u with it u would have an option to try and remember all the stuff or just forget everything - at some cost ofc - like permanent -1 INT
