You can disconnect the Atlassian SaaS Ops integration from either the Partner Hub or the Admin Hub.

From the Partner Hub

1. Navigate to Org Preferences → Integrations → Client
2. Select the relevant client from the dropdown
3. Locate the Atlassian tile
4. Click Update
5. Click Disconnect
6. Confirm to finalize the disconnection

From the Admin Hub

1. Navigate to Utilities → SaaS Ops Integrations
2. Locate the Atlassian tile
3. Click Update
4. Click Disconnect
5. Confirm to finalize the disconnection