I need to convert all values in a table and I need that change to be permanent so the table has dates and they are formatted like
If your dates are stored with the appropriate data type (date, datetime or datetime2), then they are stored without any display format.
If that is the case you need to convert them to
char(10) when selecting the data:
SELECT CONVERT(char(10), DateTimeColumn, 120)
If they are stored as a string type, you should refactor your database and store them properly. If that's impossible for some reason, you can convert twice. one from string to date, and the other one back to string:
SELECT CONVERT(char(10), CONVERT(date, DateTimeStringColumn, 104), 120)