Replace Occurences in Internal Table.

Hello Experts,

  I have internal table like shown below.

APPEND 'SO_SEL' TO itab.
APPEND 'SO_TEST' TO itab.

In the above internal can we replace ‘SO’ with only ‘S’.I tried using statement

REPLACE ALL OCCURRENCES OF REGEX  '\b(SO)\b'
IN TABLE itab WITH 'S'
RESPECTING CASE .

But its not working.Please advise.

Thanks

prabahran