HELOC on Primary home that will be convert to RENTAL

[Kevin Kim]

Hello

I own primary home in CA , East bay and now I would like to buy another primary home and keep the current home as rental. I am not sure how soon I can get new primary home (I am trying to offer this week but will see how it goes) but in case, I would like to apply HELOC before I start new home loan process. Called one of local Meriwest Credit Union and asked if I should apply HELOC as Primary or Rental but answer was kind of Primary since it is Primary now. Then the agent says once it converted to rental near future, the loan officer can reduce the HELOC... Is it good practice to open HELOC when I received pre-approval letter form lenders for new Home purchase? I can have 20% down but want to open HELOC in case if I need some extra cash.