Identify Button Clicked in GridView

I had a GridView with a ButtonField used to Select a record to display a User's details in a DetailsView. I wanted a second button to display different form for changing a Users's password, since I wanted that to be a separate option.

GridView (usersGrid):

<asp:ButtonField CommandName="Select" Text="Select" />
<asp:TemplateField>
    <ItemTemplate>
        <asp:LinkButton runat="server" ID="changePasswordButton" Text="Change Password" OnClick="usersGrid_SelectRow" />
    </ItemTemplate>
</asp:TemplateFild>

Code Behind:

protected void usersGrid_SelectRow(object sender, EventArgs e)
{
    GridViewRow row = (GridViewRow)((LinkButton)sender).Parent.Parent;
    usersGrid.SelectedIndex = row.RowIndex;

    MyDatabase.DBUtil = new MyDatabase.DBUtil();
    changePasswordDetails.DataSource = DB.GetUser(Int16.Parse(usersGrid.SelectedValue.ToString());
    changePasswordDetails.ChangeMode(DetailsViewMode.ReadOnly);
    userDeatils.Visible = false;
    changePasswordDetails.Visible = true;
    changePasswordDetails.DataKeyNames = new string[] { "UserID" };
    changePasswordDetails.DataBind();
}