Financing a new construction home

[Nu Pogody]

Newbie here, so please bear with me.

I have a primary home with a conventional mortgage and good equity built over the years.

The idea was to refinance and take some money out for a down-payment on a new construction home, move to the new home and then rent my current home out.

Unfortunately I found a new construction home I liked before I refinanced my current home and even put a deposit on it.

It will be ready in 6 or 7 months. I spoke with a loan officer and was told it would be a fraud if I refinance my current home as primary residence despite the fact I will be living in it for 6 or 7 months.

I might be able to find money for 20% down-payment on the new home but it will be difficult. I can borrow from my HELOC and against 401K and leave the mortgage on my current home as is.

So what are my options here?

My intention is to use the new home as primary residence when it is ready. Do I need to tell the bank the old property is not my primary residence anymore?

I am also not 100% decided on keeping and renting out the old house vs. selling it and using the money for investment property.