@nzaleski I have tried to get the sub record but it is returning error.
here is the way i tried to get the subrecord
var subRecord = salesorder.getSubrecord({
'fieldId': 'address'
});
var subRecord = salesorder.getSubrecord({
'fieldId': 'addressbook'
});
var subRecord = salesorder.getSubrecord({
'fieldId': 'addressbookaddress'
});