How to highlight changes/updates on a booking/reservation that requires accept/decline?

Question

Target audience: people who don't use internet and are not good with using smart phones or computers. Where: digital service on a mobile website / mobile app

1. User receives a reservation, which they can approve or decline. With details such as date and time, duration, special instructions.
2. In case they approve, the reservation is confirmed, and all good.
3. If the reservation is updated (date, time, duration and/or special instructions change), they will receive an email about the changes (overstrike on the old values, new values displayed next to old values with a red font). And they need to accept/decline on their account online.

PROBLEM: How to highlight the changes to the user as clearly as possible, on their account when they log in?

Answer 1

This is what Modal Dialogs are for

A modal dialog is a window that forces the user to interact with it before they can go back to using the parent application. A great example of this would be a prompt for saving, or the "open file" dialog. They are often used when a user is forced to make an important decision. - What is a Modal Dialog Window?

In your case, if the user has an important change you want them to accept/decline, and that you don't want them to ignore, use a modal dialog (popup) to make it impossible to use their account until they've dealt with this.

You could also use this to add other options, like to review the changes in a more suitable location on the site.

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