Ability to add reason for declining holiday request if using the'decline' button from the email request

When an employee requests holiday and the line manager receives the email request, it can be 'approved' or 'declined' by clicking said button directly in the email. This is great if the holiday is approved. However, if it is 'declined' using said button, there is no ability to input a reason as to why it is declined. To input a reason, the line manager would have to log into People HR and insert 'comments', and then click decline. Why not have the ability to do this straight from the email? Also the employee who had holiday declined and a comment added via the desktop, the comment doesn't actually appear in the email advising the request is declined, and if the employee logs in to find out the reason, it's not accessible anywhere, the link takes the employee to their dashboard.