Changing Primary Home to Vacation & Vice-Versa? Max SFR buy limit

[Varun Parkash]

1. If I own a primary home (State A) and then buy a second home (State B) as vacation home - thousands of mile away - and eventually move to vacation home due to my job change - is it possible to covert the primary home to vacation home (refinance to get lower rate - but that won't work because primary home already got the lowest rate?) and convert the vacation home to primary and have it refinanced to get the lowest possible rate?

2. I read somewhere that a person can have 4 mortgages at a time as the max limit, is it true? For a couple - this number increases to 8 if husband-wife each own their independent properties w/o having each other's names on the title docs? Please share some constructive strategies if this is not true. I know that to buy beyond 4 properties - traditional big bank financing doesn't work easily and often regional/credit/small banks give out loans once you can show them your positive cash flow & appreciation portfolio.

Appreciate all insights from amazing folks on this forum, happy RE investing :-)