You can watch any course you've finished again whenever you like, but that doesn't change your certificate or its date.
Certificates don't run out. Some say how often we suggest doing the course again, for example "Creative Education suggests doing this course again every 2 years". Your school decides when you need to.
When your school asks you to do a course again, it appears on My learning under To do with a Retake button, and the same button is on the course page. Press Retake and work through the course again. When you finish, you get a new certificate with the new date. Your earlier certificate stays in your record.
If you need a newer certificate and nobody has asked you for it, email happytohelp@creativeeducation.co.uk and tell us which course and why.