Help with if statement in field formula...

I'm trying to calculate unique commission rates for individual sales reps in one field within my input form.

I currently have this formula (calculates commission rate) in my commission field and it's working fine:

(Sold_Rate1 * 0.3 - (Sold_Rate1 - Retail_Rate1))

I would like 2 of the sales reps to get a different commission rates than all the rest.

This is what I tried placing in my Commission field and it keeps giving me errors:

-------------

if (Rep == "JQ")

{
(Sold_Rate1 * 0.3 - (Sold_Rate1 - Retail_Rate1))
}

else if (Rep == "LG")

{
(Sold_Rate1 * 0.3 - (Sold_Rate1 - Retail_Rate1))
}

else

{
(Sold_Rate1 * 0.25 - (Sold_Rate1 - Retail_Rate1))
}
-----------

I'm sure I'm missing something obvious, but I can't find anything in the help files.

Thanks.
Scott