It helped me a lot to look at the closeup pictures of the fan connector socket on the motherboard and the fan connector itself. Then I could figure out where to apply the axial rotating pressure with the plastic "spudger" (a trimmed old credit card). Needed more force to remove the 7-year old connection than I felt comfortable with. The pic's helped with the leverage point to use - just past and under the fan wires BUT not on the board itself.
Excellent guide! Moved fan from MB to MBP and installed new fan in old MB.