链表(删除节点)

我的问题是，如果用户输入一个姓氏，并且链表中有多个相同的姓氏，其中一个姓氏在head节点中。如何在不删除头节点的情况下删除其他姓氏呢?我尝试了一些我能想到的方法，但所需的节点被删除(这很好)，包括头节点(这不是我想要的…)

void NumberList::deleteCertainRecord()
{
string lname = "";
ListNode *ptr;
ptr = head;
string answer;
cout << "Please enter last name: "<<endl;
cin>>answer;
int num = 0;
char confirm;
while (ptr!= NULL){
    lname = ptr -> data.person.getLastName();
    if(lname == answer){
        num++;
        cout << "Person found : ";
        cout << ptr->data.person.getTitle()<<" " << ptr -> data.person.getFirstName() << " " << ptr -> data.person.getLastName() << endl << endl;
        cout << "Do you want to delete his/her record? [Y/N]" << endl;
        do{
            cin >> confirm;
            if(confirm=='Y'||confirm=='y'){
                    ListNode *previousNode;
                    if(isEmpty()){
                        return;
                    }
                    else if(head->data.person.getLastName() == answer){
                        ptr = head->next;
                        delete head; 
                        head = ptr;
                    }
                    else{
                        ptr = head;
                        while(ptr!=NULL && ptr->data.person.getLastName() != answer){
                            previousNode = ptr;
                            ptr = ptr->next;
                        }
                        if(ptr==NULL){
                            cout<< "Node not found!" << endl;
                            return;
                        }
                        else{
                            previousNode->next = ptr->next;
                            delete ptr; 
                        }
                    }
                    cout << endl << "Deleting..."<<endl;
                    cout << "Done!!" <<endl;
                    cout << "Exiting delete function... "<<endl;
                    return;
            }
            else if(confirm=='N'||confirm=='n'){
                break;
            }
            else{
                cout << "invalid input, please enter again!!" << endl;
            }
        }while(confirm!='Y'&&confirm!='y'&&confirm!='n'&& confirm!='N');
        cout << endl;
    }
    ptr = ptr -> next;
}
if (num == 0){
    cout << "nNo person with the last name ("<< answer << ") was found!" << endl;
    cout << "Exiting delete function... "<<endl;
    return;
}
}