Remortgage for capital rising
The amount of equity that you have in your home refers to how much of it you own compared to your mortgage. So, for example if you have home worth £200,000 and you have an outstanding mortgage of £150,000, you have an equity of £50,000. This value will only increase as you go on paying your mortgage off subject to any changes in property prices.
You can apply to unlock this equity with a remortgage, leaving the lump sum for whatever reason you have, to need it. Do note however that most lenders will require a certain amount of equity to remain in the property and will only allow you to raise funds for specific reasons as permitted by their individual criteria.