You can set an expiration date for an account as follows:
You are in the Managed Cloud Hosting > Projects section.
You have already created a project.
You have already created an SFTP/SSH user.
Select a project.
Click next to an SFTP/SSH user.
Click Set expiry.
Check the Temporary user box.
Select the time of deletion.
Click Save changes.
The expiration date has now been set for the account.