I do not know about SQL but I am guessing oracle and SQL should be very similar why don't you use sysdate +30 and sysdate +37 to get the 1st and the 7th day after 30 days

SQL> select sysdate from dual;

SYSDATE
----------
05/29/2008

SQL> select sysdate+30 from dual;

SYSDATE+30
----------
06/28/2008

Then to update you should be able to update it using straingt fwd update..

Update TableA set status='2nd Notice' where staus='1st Notice'