Setting an expiration date for wordpress roles

I need to know if there is any manual way to set expiration date for a given role.

In my website, when a person purchases a video, they are assigned a role. What I am looking for is to restrict this role to 30 days. Meaning that this person has access for this restricted content during 30 days, after that, they will go back to subscriber with no further access to the video he purchased.

Thank you and regards

Liliana

Kindly let me know if I can do this manually. I am currently using a plugin.