How to set up follow up when using SO_DOCUMENT_SEND_API1 to send email

Hi Every experts,

My client wants to send an external email from SAP with follow up function. For example, the receiver should process the email within 2 hours after receiving it, otherwise, pop up a reminder message in microsoft outlook.

Can we use function modules SO_DOCUMENT_SEND_API1 or SO_OBJECT_SEND to do it? How to do it? Is there any example?

Thanks,

Shirley