Need some help with dates

Hi.

First, let me apologize for my poor level in english, I hope you'll
understand me.

I'm new in PL/PgSQL, and I have a little problem.

I have a temporary table (temp) with only varchar. I must do a request that
fill another table (mclis) with temp's data. But on the new tables, I have a
field in date format. When I make a

update mclis
set cli_date = temp.temp1

he doesn't want because of the different formats ('column "cli_date" is of
type 'date' but expression is of type 'character varying').

In temp, my data are like 01/01/2001

I tried also
set cli_date = select case(temp.temp1 as date) but he says:
Cannot cast type 'character' to 'date' or Cannot cast type 'character
varying' to 'date'.

Does anyone has an idea ?