Update one column in different conditions

Question

Is there any way by which I can merge following two update statements into a single statement without using plsql. Here the same column of one table is being updated in different conditions.
UPDATE week_table
SET present_week=NULL
WHERE week_table.pay_statusk=(
                    SELECT value
                    FROM panel
                    WHERE pname='PRESENT_WEEK')
UPDATE week_table
SET present_week='Y'
WHERE week_table.pay_status=(
                    SELECT value+1
                    FROM panel
                    WHERE pname='PRESENT_WEEK')
--waiting for a solution, thanks in advance.
null

Answer 1

Or like...
SQL> select * from week_table;
PRESENT_WE PAY_STATUS                                                          
X                   1                                                          
X                   2                                                          
SQL> select * from panel;
PNAME                     VALUE                                                
PRESENT_WEEK                  1                                                
SQL> UPDATE week_table
  2  set present_week = decode(pay_status,(select value
  3                                       from panel
  4                                       where pname = 'PRESENT_WEEK'),null,
  5                                      (select value+1
  6                                      from panel
  7                                      where pname = 'PRESENT_WEEK'),'Y')
  8  WHERE week_table.pay_status=(
  9                        SELECT value+1
10                        FROM panel
11                        WHERE pname='PRESENT_WEEK')
12  or
13   week_table.pay_status=(
14                       SELECT value
15                        FROM panel
16                        WHERE pname='PRESENT_WEEK');
2 rows updated.
SQL> select * from week_table;
PRESENT_WE PAY_STATUS                                                          
                    1                                                          
Y                   2