def revise_names(x, n=None):
    """
    Revise case names, ensuring they are not empty or missing.

    Parameters:
    - x (list or None): A list of names (or None).
    - n (int, optional): Expected length of names. If not provided, it defaults to the length of x.

    Returns:
    - list: A revised list of names with missing names replaced by default names.
    """

    # If n is not provided, use length of x
    if n is None:
        n = len(x)
        if not isinstance(x, list):
            raise ValueError("Expected a list of names.")

    # Default name list (can be customized)
    default_names = [f"Case{i+1}" for i in range(n)]

    # If x is None, use default names
    if x is None:
        return default_names

    # Replace missing (None or empty) names with defaults
    revised_names = [name if name else default_names[i] for i, name in enumerate(x)]

    return revised_names
