SQL & PL/SQL

Hi,

I need to remove '&' from a string.
example:
string = 'HH&GG',
desired result = 'HH GG' OR 'HH,GG'

Tried 'replace', 'substr' functions, along with 'set ESCAPE '&'.
They don't work. '&' is treated as an input place holder. How can replace/remove an '&' from a string?

Thanks,
Radhika.