As you may already know, you can re-authenticate Salesforce from Cloud Elements 2.0. However, you can also do this programmatically through API calls. Follow the steps below.
1. Make a GET request to /elements/sfdc/oauth/url.
curl -X GET \
'https://api.cloud-elements.com/elements/api-v2/elements/sfdc/oauth/url?apiKey=<your_api_key>&apiSecret=<your_api_secret>&callbackUrl=<your_callback_url>'
2. Navigate to this URL to get the code as you would for the OAuth 2.0 flow.
3. Get the current instance configuration.
curl -X GET \
https://api.cloud-elements.com/elements/api-v2/instances/<instance_id> \
-H 'Authorization: User <Your_user_secret>, Organization <Your_organization_secret>' \
-H 'accept: application/json'
4. Take the body of the response from step 3 and delete the oauth.user.token
and oauth.user.refresh_token
5. In the same body add a "providerData" object that contains the code.
"providerData": { "code": "xxxxxxxxxxx" }
6. Now use the following endpoint with the body from the response in step 4 and 5.
PUT https://api.cloud-elements.com/elements/api-v2/api-v2/instances/{instanceId}?reAuthenticate=true
7. Make sure that in Step 6 you pass the correct authorization headers and OAuth token.