Partner Moving In

Hi All,

I rented my apartment to a tenant 2 months ago for an initial fixed 6 month period under an Assured Shorthold Tenancy Contract. The tenant has now asked if her partner can move in which I am fine with except I'm not sure how I should go about this in terms of the tenancy contract, paperwork etc.

Do I now need to produce a new Tenancy Contract starting from the date her partner moves in or can I continue with the current agreement until the 6 month period has ended?

Thanks in advance,
Mike