如何使用MVVM从不同的xaml页面更改属性？

public class PersonViewModel : INotifyPropertyChanged
{
    private string _name;
    public string Name
    {
        get { return _name; }
        set
        {
            if (_name != value)
            {
                _name = value;
                OnPropertyChanged(nameof(Name));
            }
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;

    protected virtual void OnPropertyChanged(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

public partial class MainPage : ContentPage
{
    public MainPage()
    {
        InitializeComponent();
        BindingContext = new PersonViewModel();
    }
}

<Label Text="{Binding Name}" />
<Entry Text="{Binding Name}" />
<Button Text="Change Name" Command="{Binding ChangeNameCommand}" />

public class PersonViewModel : INotifyPropertyChanged
{
    // ...

    public ICommand ChangeNameCommand { get; }

    public PersonViewModel()
    {
        ChangeNameCommand = new Command(ChangeName);
    }

    private void ChangeName()
    {
        Name = "New Name";
    }

    // ...
}