I ended up doing this which works fine, but I really would have like to use the UPDATE. Some day...

SELECT iAccts
SCAN
	SELECT crsFundAcctDisc
	LOCATE FOR crsFundAcctDisc.Acct_ID == iAccts.Acct_ID
	DO WHILE .T.
		IF FOUND()
			REPLACE iAccts.FootNote WITH ALLTRIM(iAccts.FootNote) + '('+ ALLTRIM(STR(crsFundAcctDisc.FootNote))+')'
			CONTINUE
		ELSE
			EXIT
		ENDIF
	ENDDO
	SELECT iAccts
ENDSCAN