how to set populatexml to my secound class's method

public response populatexml(string xmlresponse)
{
if(xmlresponse == string.empty)
{
return null;
}
xmldocument reps = new xmldocument();
reps.loadxml(httputilities.htmldecode(xmlresponse));

response res = new response();
 this.parseresponse (res, reps)
return res;
}

public string setchanneldata(string xml)
{
here i want to set the response of the 1st class xml response.

}