Impact on Mortgage when you change property type after closing

[Account Closed]

I am currently exploring ideas of buying single family property and turning it into multi family or commercial. It will be either fix and flip or fix and hold.

If you are financing a deal through conventional or /Fannie mae HomeStyle / FHA 203b as single family in the beginning, what are the potential issues you may face when you eventually convert it to multi familly? ( in both case the property is already in multi family zoning or not in multi family zoning )