Your Tettra account can only be associated with one Slack workspace at a time. To disconnect your existing Slack integration, visit the Team settings > Integrations page and click 'Remove':
Note that removing the Slack integration has some effects that cannot be undone. Disconnecting your Slack workspace from your Tettra account will:
Prevent users from that Slack team from logging in using Slack. Existing users should create a password to ensure they continue to have access to Tettra.
Remove any pending invitations to users in that Slack team
Unassign any suggestions to users in that Slack team
If you'd then like to connect a different Slack workspace, follow the instructions here.