I need to send an email reminder 30 minutes before.

[nikhilgadodiya]

I need to send an email reminder 30 minutes before the selected date and time in a field called "Next action date and time" so that user can be reminded to work on a ticket.

I had created a notification with when to send being as shown below but it is not working please provide me a way to achieve this.

[nikhilgadodiya]

This field contains a subtracted time..I did it separately and after adding 5th parameter it is working fine..

Thanks for help..