Generally there isn't flexibility. They have a different loan products for properties that aren't going to be used a a personal residence. They may make a different loan for rental properties, and one for vacation properties.
These other products will have different interest rates and different down payment requirements.
Depending on the neighborhood you may run into issues if you buy and immediately rent. Generally this is due to a high number of rentals already in the condo association. Some government loan programs can't be used in these situations.
You may have to wait before buying.