I have tried to get the Conversation History with Attributes using time Interval Input. I used /api/v2/analytics/conversations/details. But I am not getting the Attribute. For getting Attribute value, I have used another API like /api/v2/conversations/{conversationId}. Please Assist on this, How can I get the  Conversation History with Attributes using Single Request?

If you are looking for participant attributes for reporting, ie all calls over x period, try using the jobs api POST /api/v2/analytics/conversations/details/jobs

From there it will run in async, so grab the ID from that request, you need to check if complete (https://developer.genesys.cloud/devapps/api-explorer#get-api-v2-analytics-conversations-details-jobs--jobId-)

then fetch the results 

https://developer.genesys.cloud/devapps/api-explorer#get-api-v2-analytics-conversations-details-jobs--jobId--results

Alternatively, consider using the amazon event bridge integration to pull the data over to your data storage instead. Check out the integration dev cast (https://www.youtube.com/watch?v=4Eg-oDNcShA&t=1105s) around the 18:00 mark for an overview on that.