MS SQL get all dates prior to given date

How do I find all dates prior to a given date? I have the following partial script:

select trandefid from NodeSynchronizationHearingState where CaptureCompleteDate < GETDATE()

That will select all records where CaptureCompleteDate is prior to today's date. How do I return records prior, say, 12/15/2018? This seems like a simple question but I'm not finding what I'm looking for on Google.