React: How to pass function as props from Functional Parent component to child

You can take this as an reference with live example demo https://codesandbox.io/s/musing-mendeleev-6fvyx

function App() {
  const [status, setState] = React.useState(false);
  const [text, setText] = React.useState("");
  const handleClick = () => {
    this.setState(prev => ({ status: !prev.status }));
  };
  const handleChange = e => {
    this.setState({ text: e.target.value });
  };

  return (
    <>
      <button onClick={handleClick}>Open photo entry dialog</button>
      <ChildComponent
        isOpen={status}
        text={text}
        handleChange={handleChange}
        handleClick={handleClick}
      />
    </>
  );
}

const ChildComponent = ({ isOpen, text, handleChange, handleClick }) => {
  return (
    <>
      {isOpen && (
        <Model
          status={isOpen}
          handleClick={handleClick}
          text={text}
          handleChange={handleChange}
        />
      )}
    </>
  );
};

You need to remove the parentheses behind passedFunction, because otherwise you are executing the function first and passing the result to the child afterwards. Pass your function as it is via passedFunction={passedFunction}.

const ParentComponent = () => {

  const initialModalProps = { ... };
  const [modalProps, setModalProps] = useState(initialModalProps);

  const passedFunction = () => {
    setModalProps(initialModalProps);
  }

  return (
    <div>
      <Modal
        show={modalProps.show}
        response={modalProps.response}
        passedFunction={passedFunction} />
    </div>
  );

};