If your lease has been generated, it will not be possible to change the email address on the lease. 

However, you will be able to change the communication email address of one or more signatories who had an email address at the time the lease was generated. 

It is very simple to do this: 

1. I go into the lease management tool

2. I press the button with the pencil icon on the left next to the signatories email addresses

3. I modify the email address concerned

4. I press the paper aeroplane icon to send the lease back to the new communication address

That's it, the signatory will receive the lease at his new email address.