Can I sublet my room?

This would need to be discussed with your landlord/agent and depend upon the contract or tenancy agreement you have entered into. 

A lot of landlords will not allow you to sublet your room but may allow you to find a (suitable) “replacement” if, for whatever reason, you need to move out of a property before the end of your contract. However they are not legally obliged to do this so you will need to discuss this with them before trying to find a replacement.