The issue you are having, is that you are attempting to specify the format incorrectly. The Format() function always returns a character string. Take a look in the Scripting Index for examples on how to use the Format() function.
The JSL below will convert a Character column with the data formatted as
08/21/2020 11:17:31
and convert it into a JMP Date/Time column
:Time << Data Type( Numeric );
:Time << Set Modeling Type( Continuous );
:Time << Input Format( "m/d/y h:m:s" );
:Time << Format( "m/d/y h:m:s", 23 );
Jim