A question about mortgages?

A question about mortgages? 

My question is about mortgage renewals. 

In this scenario, a person or couple gets a mortgage on a house with a 5% down payment and obviously gets the biggest mortgage they can so as to live in a beautiful house. Five years later the mortgage is up for renewal and the market is down. Does this mean that the owners can no longer approve for a mortgage on the same house because they would no longer have a 5% or more equity stake in the home? 

I'd really like to know the answer to this question and wouldn't mind a bunch of answers along with the country you are writing from. If answering this question please feel free to add a link back to your website.

https://istockhomes.com/professional_advice/question-about-mortgages

Thanks 

Brad