If you wish to end the tenancy, you will need to advise the landlord in writing, make sure you give the appropriate notice and notice period and ensure your notice is delivered within a suitable time.
Your notice of intention to vacate must be in writing, be signed by you, give a reason why you are moving and state the date you plan to leave, taking into account and allowing for the amount of time required under notice periods. It is also a good idea to include a forwarding address.
The notice period you will have to give your landlord will depend on the reason you are vacating and the type of lease you have. Where you have a fixed term tenancy, the end date on the notice cannot be before the end date of the agreement. In most cases, if you provide a date earlier than this, you are breaking the tenancy agreement and may be subject to fees.