The link below is of my great uncle but they spelled his last name wrong. It is Callirgos not Gallirgos. How can I get that fixed.
FamilySearch's index-correction function is still limited in scope, and it looks like it does not extend to this collection. Therefore, you cannot correct the index -- but despite the error, the index served its purpose, because you found the record.
What you can do is edit the source citation on Gilberto's and Emilio's profiles, adding something about the mis-transcription in the Describe the Record (Notes) field.
(It's an understandable error: the only difference between this clerk's Cs and Gs is a small loop at the top of his Cs.)