Discuss What advice would you give the caller to find out how to tell which insurance would be her primary and why that matters. And, if she submitted a claim, should it be filed with multiple carriers?

Description
A phone call came into the help center from an older patient. She asks, “Which of my insurances is my primary insurance?”
She has been on her husband’s HMO for a long time. Recently she got a new job that offers health insurance, as well.
Discuss
What advice would you give the caller to find out how to tell which insurance would be her primary and why that matters. And, if she submitted a claim, should it be filed with multiple carriers?