You should extend the current lease by 2 more years ie Dec 2022 to coincide with the expiry of the new lease for additional space for 3 years expiring Dec 2022.Given that we need to do renovation, you should get the landlord to give us 1-2 months renovation fitout periods.Given we are taking more space and extending the lease till Dec 2922, it is not unusual to get landlord to offer us 2-3 months rents free for the new 3 years lease. Please try to negotiate with the landlord on this.