replace " with nothing

We are converting from Oracle to Postgres.  An Oracle script contains
this line:
select replace(firstname,'"'), memberid, emailaddress from members;

in an effort to replace the " with nothing.  How can I achieve the same
result with Postgres?

Here's the Postgres error I get:

select replace(firstname,'"'), memberid, emailaddress from members;
ERROR:  function replace(character varying, unknown) does not exist
LINE 1: select replace(firstname,'"'), memberid, emailaddress from m...

Thanks.