Users can be moved from Commit to Flex, and vice versa, from with the Citrix Cloud management interface.
Note: As per the “What are Commit and Flex Licenses” section of this FAQ, a Commit license can only be reassigned after 30 days of inactivity.
Extract from the Citrix Service Provider Program FAQ: https://www.citrix.com/content/dam/citrix/en_us/documents/become-a-partner/citrix-service-provider-program-faq.pdf
Do Citrix Service Providers have access to Citrix Cloud for their customers?
Yes, Citrix Service Providers can purchase Citrix Cloud services to support their customers.
Please note that Citrix Cloud has additional requirements: