Database for testing - problems with updates

Hello

we try to use a database for a test. We write into a table the date of two days ago and of three days ago. These dates are our variables in the test.

The problem: The dates are not updated (example: variables two days ago 14/7 and 15/7, variables of today 14/7 and 15/7, but it should be 16/7 and 17/7)

Our stored procedure:

USE [DATABASE]
GO
/****** Object:  StoredProcedure [dbo].[Listsearch_Report_Dates_Procedure]    Script Date: 19.07.2017 12:25:15 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

ALTER PROCEDURE [dbo].[Listsearch_Report_Dates_Procedure]
AS
BEGIN

Update dbo.Listsearch_Report_Dates

Set Vorgestern = CONVERT(VARCHAR(6), getdate()-2, 4), 
Vorvorgestern = CONVERT(VARCHAR(6), getdate()-3, 4) 

select * from Listsearch_Report_Dates
END