let
    Source = Excel.CurrentWorkbook(){[Name="weekone"]}[Content],
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Column1", type date}}),
    FirstRecord = #"Changed Type"{0},
    RecordValue = Record.Field(FirstRecord,"Column1")
in
    RecordValue

= DateTime.Date(Record.Field(Excel.CurrentWorkbook(){[Name="weekone"]}[Content]{0},"Column1"))

= DateTime.Date(Excel.CurrentWorkbook(){[Name="weekone"]}[Content]{0}[Column1])

= DateTime.Date(Table.FirstValue(Excel.CurrentWorkbook(){[Name="weekone"]}[Content]))