Buying existing house with additional building lot

[Peter Pierzchala]

I'm looking into a house to live in flip that comes with an additional second lot that is buildable. Both properties are listed on the same deed as parcel one and parcel two. To sell off the second lot, from what i understand, I'll need to pay off the mortgage used to buy both at the time of sale to make a clean title. Is there any issue with that strategy, like being in the middle of a flip and not knowing when the sale might happen? Is there a better way to separate out the two properties for a cleaner sale of the lot without messing with the mortgage?

Thanks for any help!