Ideally each call remains in queue for 5 minutes.
If you want to reduce/change the time as per requirement, you can follow the below steps:
Step 1: Login to your account (web.callhippo.com)
Step 2: Go to Numbers > Number Settings > Call Queue
Step 3: Turn on Call Queue > Click on Edit button and set the duration
The call will remain in the queue for the duration you have set and at last go voicemail.
For any queries, please contact us at support@callhippo.com