How to convert the input and output mode of GPIO？

[tsuiwade]

I'm using GPIO to simulate the timing of a 'one bus' device.
I need GPIO to go from output mode to input mode.

var output = gpio.output(36);
var input= gpio.input(36);

Then, the error shows

Unhandled exception:
Already allocated pin: 36

Do I need to release first？

gpio.dispose(); ?

plz help!