Hi Moritz
If you need to have your Bot Service in a different location to reduce latency or comply with data residency requirements, you would typically need to create a new Bot Service in the desired region and then migrate your bot code, configurations, and any relevant data to the new service.
I guess it is not possible to directly change the subscription of an existing Azure resource, including the Bot Service.
https://azure.microsoft.com/en-us/search/?q=azure+bot+services&docsids=
if this helps kindly accept answer, thanks much