In ASK we get many enquiries from students who want to leave their tenancies early and some who have changed their minds before they've even moved in. On very rare occasions a tenancy agreement may have a clause allowing you to serve notice to leave early, but if yours doesn't have one you can normally only be released or have the terms of the tenancy varied if the landlord agrees to it. This is still the case, even if you never moved in.
We advise students to talk to their landlord about why they want to leave and see if the landlord is willing to negotiate. Most landlords will only agree to end the tenancy early if there is a replacement tenant to take over from you - you can try advertising to students on Facebook groups, like Keele Student Life, and the Keele Studentpad message board.