From the given code the fetch from is not working in the dialog box

ERPNext
1

{
fieldtype: ‘Link’,
label: __(‘Sales Officer’),
fieldname: ‘sales_officer’,
options: ‘Employee’,
depends_on: ‘eval: doc.designation == “Sales Officer”’,

              get_query: function(doc) {
                return {
                    filters: {
                        'designation': 'Sales Officer'
                    }
                };
            }
        },
          {
            fieldtype: 'Data',
            label: __('Sales Officer Name'),
            fieldname: 'sales_officer2',
            fetch_from: 'sales_officer.employee_name',
            depends_on: 'eval: doc.designation == "Sales Officer"',
              get_query: function(doc) {
                return {
                    filters: {
                        'designation': 'Sales Officer'
                    }
                };
            }
            
        },
2

Hy @neha

Check this code
I hope It’s working

let d = new frappe.ui.Dialog({
                title: 'Enter details',
                fields: [
                    {
                        fieldtype: 'Link',
                        label: __('Sales Officer'),
                        fieldname: 'sales_officer',
                        options: 'Employee',
                                      get_query: function(doc) {
                return {
                    filters: {
                        'designation': 'Sales Officer'
                    }
                };
            },
                        onchange: function () {
                            var salesOfficer = d.get_value('sales_officer');
                            if (salesOfficer) {
                                frappe.call({
                                    method: "frappe.client.get",
                                    args: {
                                        doctype: "Employee",
                                        name: salesOfficer,
                                    },
                                    callback(r) {
                                        if (r.message) {
                                            var emp = r.message;
                                            d.set_value('sales_officer2', emp.employee_name);
                                        }
                                    }
                                });
                            }
                        }
                    },
                    {
                        fieldtype: 'Data',
                        label: __('Sales Officer Name'),
                        fieldname: 'sales_officer2',
                        read_only: true,
                    },
                ],
                primary_action_label: 'Submit',
                primary_action: function (values) {
                    // Your primary action code here   
                    d.hide();
                }
            });

            d.show();

Thank You!