If, for whatever reason, you want or need to move out of your accommodation you will probably have to find a replacement to take over your licence or tenancy.
Unless you find a replacement, you will usually be liable for the rent until someone else is found.
Below are some links to groups and noticeboards and websites where you can advertise your room and browse posts from students seeking accommodation.
There should not be a prohibition in your contract saying you can't assign your tenancy - it usually says you can do it but you will need the landlord's permission. There may also be a charge for this.
Once a suitable replacement tenant has been found then in order to transfer legal rights and responsibilities from yourself to the new tenant, the landlord should either create a new tenancy or a deed of assignment. All parties to the original and new contract will need to agree – including the landlord.
You will also need to sort out what happens in relation to things like utility bills and tenancy deposits.
We would recommend that you seek advice from SU Advice if you are going through the process of finding a replacement tenant, to ensure everything is being done properly.