let
Source = "Jan 1, 2017 6:01:12 AM PST",
#"Converted to Table" = #table(1, {{Source}}),
#"Extracted Text Before Delimiter" = Table.TransformColumns(#"Converted to Table", {{"Column1", each Text.BeforeDelimiter(_, " PST", 0), type text}}),
#"Parsed Date" = Table.TransformColumns(#"Extracted Text Before Delimiter",{{"Column1", each Date.From(DateTimeZone.From(_)), type date}})
in
#"Parsed Date"