with t as 
(
  select * from table(sys.odcivarchar2list('AAA','BBB','CCC',':DDD','EEE'))
)
select regexp_replace(column_value, ':{0}(.+)', '"\1"') result from t;


RESULT                                                                         
-------------------
"AAA"                                                                           
"BBB"                                                                           
"CCC"                                                                           
":DDD"
"EEE"