Taking out a second mortgage is not the same as remortgaging. A remortgage replaces your existing mortgage with a new one, either with your current lender or a different lender. This can be used to secure a new rate, release equity from your property, or both.
A second mortgage, also known as a secured loan or second charge mortgage, allows you to borrow additional funds against your property's equity while keeping your existing mortgage in place. This can be beneficial if you're on a competitive mortgage rate or would incur early repayment charges by remortgaging.