Return string text if date field = null

Hi Guys,

I'm still fairly new to calculations so would appreciate your help.

I have a placeholder on a web desk report that shows a field on our change request process called {_ImplementationDateDispla}.

However what i would like to do is display a text string if this field is empty/null - e.g. 'There is no current ETA'

The object in the calculation sites as: Change.IncidentChanges.Change._ImplementationDateDispla

Any help appreciated.