Extending a lease is something only the landlord can do. Therefore, ask your landlord to go the tab "My rentals" and click "Extend lease". The landlord will have to enter the new end date, so make sure to discuss that beforehand. An extension contract will then be sent to you via e-mail and text for electronic signing.
Note that you cannot extend a contract where you have unpaid invoices. If you have outstanding payments linked to the contract, make sure they are paid and registered with Qasa before you sign.
This article is about long-term rentals. For information on vacation homes look here!