Remortgage means paying off the mortgage from the bank where you previously took out a mortgage and applying for a new mortgage with another bank.
The first thing to consider is whether your current mortgage is still within the penalty period, which is generally 2 to 3 years. If your current mortgage hasn't passed this period, you'll have to pay interest penalties when you make an early repayment.
Should you qualify for a new mortgage, you'd be required to sign a mortgage contract, which would incur legal fees. However, cash rebates and legal fee waiver are usually offered to mortgage takers, so that would help you to cover some of the extra costs. Besides, if the new mortgage interest is lower than the current rate, extra savings in monthly interest can add up to offset the penalty expenses and other expenses.