string Caption {get; set;}

// find all the table panes (table panes hosting map data)
var tablePanes = FrameworkApplication.Panes.OfType<ITablePane>();
var tablePane = tablePanes.FirstOrDefault(p => (p as ITablePaneEx)?.Caption == "oldcCaption");
var tablePaneEx = tablePane as ITablePaneEx;
if (tablePaneEx != null)
  tablePaneEx.Caption = "newCaption";

// find all the external table panes (table panes hosting external data)
var externalPanes = FrameworkApplication.Panes.OfType<IExternalTablePane>();
var externalTablePane = externalPanes.FirstOrDefault(p => p.Caption == "oldcCaption");
if (externalTablePane != null)
  externalTablePane.Caption = "newCaption";