import re


def reformat_name(x: str) -> str:
    """
    Reformats the given column name to lowercase with underscores.

    Args:
        x: the name to convert

    Returns:
        The converted name.
    """

    y = re.sub(r'_+', '_', x.lower())

    y = y.replace('tronchanter', 'trochanter')

    return y