I looked up and checked his manual. I guess I could have provided the link to it.I haven't looked your model up But I agree with Darryl G ............ I have seen those in different places on different mowers....
Some places on Z turns you have to lift the seats, some are towards the front side of the wheels and a lot of them are in the rear of the mower .........
Your owners manual will tell you are you can Google your specific mower ..........
I looked up and checked his manual. I guess I could have provided the link to it.
Did it show where the release is ???