"As to form only" means that the tenant's attorney can suggest wording changes as long as the changes are not substantive or add/remove any obligations or benefits. Put another way, the tenant must agree to the landlord lease, but minor word changes can be negotiated."As to form and content" means that the tenant's attorney can suggest substantive changes that add/remove obligations or benefits. Put another way, the tenant may not have to agree to the landlord's lease if the tenant's attorney wants to make a major change and the landlord refuses to agree.