Can you remortgage with the same lender?
Lots of lenders now are offering something called a product transfer, which means at the end of your deal you can switch to a new rate to avoid going on to Standard Variable Rate. Product transfers can be quicker and easier than a full remortgage to a new lender because you're already an existing mortgage customer of that particular bank.
However, the best option for you will depend on what your current circumstances are and why you're looking to remortgage, for example, if you're looking to remortgage and raise some cash for home improvements, you might be able to obtain a further advance on your current deal.
Remember though, while you can remortgage with the same lender, it's important that you understand all of your options before doing so, it might be that there is a better deal for you with another lender on the market, so a whole of market comparison is crucial before you commit to anything.