You need to use a solicitor for any remortgage transaction, who will take care of the mechanics of adding and removing legal charges and repaying the previous lender (if there is one). I’m often asked how remortgaging actually works in practice, and that’s the answer: you’ll agree a loan with the new lender, your solicitor will receive the money and use it to pay back the old lender, and any balance left over is deposited in your bank account.