There are two main possibilities if you want to vacate the premises before your lease expires. You may ‘assign’ the lease to another tenant who takes over responsibility for paying rent to the landlord (but see below). Or you may continue to pay the rent, but sub-let the space to another tenant, from whom you in turn collect rent. However, your lease will probably limit or impose conditions on your ability to follow either course, and you need to understand these limitations fully before you sign the lease.
Some leases will incorporate a ‘break clause’, which gives the landlord or tenant (or both) the right to walk away from the lease at a specific point.
The clauses in your lease relating to assignment and sub-letting can have a very important effect on your future flexibility. You should make certain that your chartered surveyor or solicitor explains exactly what you are being asked to agree to, and its possible implications.