Tenant wants out early

Tenancy Types and Management

Slightly strange scenario in so much that 2 months into a 12 month tenancy (using the RLA AST which has a 2 after 6 break clause) the tenant wants out of the agreement and out of the property. I have agreed, that suits both of us and I would like them gone sooner rather than later and have suggested they go one month from now. It was their suggestion but is there anything the tenant should say in writing e.g they agree to waive the T's &C's of the tenancy agreement and agree to go by a certain date? Any advice gratefully received.