Let's list all the possibilities (there are 8).

Top Hat Graduation Cap Women's Hat

T T T

T T H

T H T

T H H

H T T

H T H

H H T

H H H

Since I have revealed one of the hats covers "heads" AFTER inspecting both caps, You are left with six possibilities. (Note that I did not just pick the graduation cap by default).

That said, it is important to reveal the assumptions made to list the six possibilities:

- If I cannot reveal a "heads" that particular turn is cancelled and we start over.
- If I inspect both hats then I am obligated to reveal the "heads" regardless of whether the heads is below the Graduation cap or the women's hat.

Top Hat Graduation Cap Women's Hat

T H T

T H H

H H T

H H H

T T H

H T H

If your strategy is to not switch then the probability of winning is half. If your strategy is to switch the probability of winning is 2/3.