I want to reduce licences for photoshop and acrobat and cahange to/add creative cloud licences. how do I do that?
it seems like it's just possible to add licences and not reduce.
Do take a look at https://helpx.adobe.com/enterprise/using/add-products-and-licenses.html for details on adding or removing licences. Removing licenses is possible in the "Renewal window", which starts 30 days before the anniversary date.