1) for replace():
The following example replaces occurrences of "J" with "BL":

SELECT REPLACE('JACK and JUE','J','BL') "Changes"
FROM DUAL;

Changes
--------------
BLACK and BLUE

2) for translate():

SELECT TRANSLATE('2KRW229',
'0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ',
'9999999999XXXXXXXXXXXXXXXXXXXXXXXXXX') "License"
FROM DUAL;

License
--------
9XXX999


The following statement returns a license number with the characters removed and the digits remaining:

SELECT TRANSLATE('2KRW229',
'0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ', '0123456789')
"Translate example"
FROM DUAL;

Translate example
-----------------
2229

have fun!!