To end a tenancy agreement, you should serve notice to the landlord directly in writing. Your contract is between you and your landlord, so there is no need to notify OpenRent.
When to Serve Notice
This will depend on the notice period stated in your contract. Where you're part of a Rent Now tenancy, you can find out what your notice period is by locating your tenancy here; just go to the section "Interrupting or Ending this Agreement".
If you want to leave before the notice period in the contract would allow, then you need to talk to the landlord directly. Agreements can be terminated if everyone agrees, but the landlord would not normally be obliged to end the agreement early.
How to Serve Notice
We recommend that, where possible, you give notice on the last day of your rental period (the day before your next rent payment is due). This ensures there are no gaps in any rent owed after your last payment.
The safest way to give notice is in person with a means of proving receipt; e.g. asking the landlord to confirm in writing that they received your notice.
If that's not possible, the next best thing is to send your notice by recorded delivery. This gives you proof that you sent the notice but not necessarily that the landlord received it.
If neither of these options are available, you can give notice by email, providing that your contract states this is acceptable. However, giving notice by email can make it difficult to prove that the landlord received your notice if there is a dispute.
When is notice considered to be 'served'?
It does not have to be proved that the recipient has received the notice, but the notice isn’t served until it has arrived (e.g. 2 days after sending for first class post).