Different interest rates for primary or vacation homes

Hi All, 

Wondering if anyone has experience with this area of lending: it seems like lenders offer different interest rates based on whether a home is a primary residence or 2nd/Vacation property. Does anyone know whether the lender has any discretion on this? (For example, if one's primary residence is a rental therefore this would be their first mortgage.) Of course I don't want to misrepresent my intent with the property to the bank, but I'm happy to attempt to negotiate if there is any chance for wiggle room. 

Thanks!