If you need to extend your visa for any reason (such as switching courses, adding a placement/study abroad year, advancing from undergraduate degree to masters or changing from Tier 2 work permit to Tier 4) from within the UK it is possible. There may be restrictions and you will require confirmation on a new course plus proof that previous one was completed successfully; you can remain in the country while waiting for a decision.
Additionally, to extend a Student Visa you will require funds sufficient to cover tuition fees and living costs. Make sure your funds are available and easily accessible in an account in your name – details on this can be found on our Money page.
As it is essential that you do not overstay your visa, the Home Office expects you to leave within three months of its expiration unless additional permission has been granted from them for extended stay – such as an educational visa application – otherwise leave as per the date on your visa expiry notice.