how to use fonction to display modal ?

when I stage the component to change the boolean value of the isOpen parameter, it doesn't show the modal.

```
<ReportModal
  isOpen={this.state.isOpenModal}
  title="Sorun Bildiriniz"
  buttonText="Gönder"
  iconConfig={IcomoonConfig}
  menuOptions={this.menuOptions}
  onPress={selectedItems => {
    this.onPress(selectedItems);
  }}
/>
```

What to do ?