def change_sample(self, old_samp_name, new_samp_name, new_site_name=None,
                      new_er_data=None, new_pmag_data=None, replace_data=False):
        """
        Find actual data objects for sample and site.
        Then call Sample class change method to update sample name and data..
        """
        sample = self.find_by_name(old_samp_name, self.samples)
        if not sample:
            print('-W- {} is not a currently existing sample, so it cannot be updated'.format(old_samp_name))
            return False
        if new_site_name:
            new_site = self.find_by_name(new_site_name, self.sites)
            if not new_site:
                print("""-W- {} is not a currently existing site.
Adding site named: {}""".format(new_site_name, new_site_name))#sample.site or '*empty*', sample)
                new_site = self.add_site(new_site_name)
        else:
            new_site = None
        sample.change_sample(new_samp_name, new_site, new_er_data, new_pmag_data, replace_data)
        return sample