def update_indices(acc_info_to_update):
    """
    Recover indices that still need to be updated
    """
    index_unknown = acc_info_to_update.index[acc_info_to_update["Direction"]=="Not_known"]
    index_flag = acc_info_to_update.index[acc_info_to_update["Direction"]=="FLAG"]
    index_all_unknown = index_unknown.union(index_flag)
    return index_unknown,index_flag,index_all_unknown