Yes, you can apply for a CAS to extend your visa to retake modules, and if we have confirmed you need to remain in the UK to complete your studies. We would also recommend to first check our "CAS for extending your visa" webpage to make sure you meet all the other eligibility requirements for a new CAS, as there are a number of factors that we must take into account.
If eligible, you will then need to request a new CAS to support your visa application. Our webpages provide helpful guidance on the information you will need to support your application.
You will then need to send your completed CAS request form to studentvisa@greenwich.ac.uk. Make sure to do this in plenty of time before your visa expires as it can take up to 10 working days to process your request. Please note that you can only apply a maximum of 3 months before the end date of your current visa.