Hello Hari Kumar G,
Thanks for your question.
Deleting and recreating the trial will not reset your managed instance offer as it has been exhausted. At the beginning of the new month, it will be renewed.
Once renewed I will recommend you stop the instance manually at any time you are not using the service to avoid using up your free monthly vCore hours.
Details of this offer are detailed here: Try Azure SQL Managed Instance for free (preview)
Regards,
Abiola
You can mark it 'Accept Answer' and upvote if this helped.