Adding a new name to tenancy agrement

Hi,
I have a tenant moving in this month.

Tenancy document is prepared using OpenRent tenancy creation service.

Tenant’s family (husband and 10 year old child) are not in the UK now.
They will join her in 2 months time.

I hope I cannot include the names of her husband and child now as they are not in the country now.

When her husband and child joins her, do I need to cancel this tenancy agreement and create a completely new tenancy agreement or
will I be able to manually add their names (may be husband’s name alone, child is only 10 year old) to the tenancy agreement which I will be creating for her now?

Thanks,

Maybe read this before asking?

As for a minor child you’d never put them on the lease. What would be the reason for doing so?

Thanks Per for the link.
It looks like it will be easy if I start a new tenancy after 2 months when the tenant’s husband comes to the UK. So, I have to cancel the current tenancy after 2 months return the deposit, then start a new tenancy again.

Is there a standard tenancy agreement format I can download and use at that point?

I hope I need to collect the deposit and register the deposit,
I need to prepare new inventory and I need to provide a new how to rent guide at that time.
Thanks,