Hi @Steve Powell ,
Welcome to Microsoft Q&A forum and thanks for reaching out.
Unfortunately as of today you cannot re-use an existing Integration runtime (already in use by ADF/Synapse) with Azure Purview. As per my conversation with internal team, product is working on implementing this feature but no definite ETA at the moment.
It has been called out in the public documentation here: Create and manage a self-hosted integration runtime
Here is a similar feedback provided by other users, please feel free to upvote and/or comment on this to increase the priority of the feature implementation: https://feedback.azure.com/forums/932437-azure-purview/suggestions/42522979-reuse-existing-integration-runtime
Hope this info helps. Do let us know if you have further query.
Thank you
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