REPLACE - replace all occurrences of a substring with a new substring, starting at a specified character position.
REPLACE(InputString, OldString, NewString, Char_Offset)
Examples:
REPLACE("string with another string in it", "string", "STRING") ; "STRING with another STRING in it"
REPLACE("string with another string in it", "string", "STRING", 2) ; "string with another STRING in it"
REPLACE("string with another string in it", "string", "") ; " with another in it"