Once you mark a proposal as Lost on your end, your customer will still be able to access the link you shared.

But they will only see just enough to help them reengage with your company and avoid resending the quote to, let's say, competitors.

Here is what they will see:

Example of a Consumer view of Lost:

When the consumer views this page, the person assigned to this proposal (presenter) will get an email alert. So you can take an action to reengage that customer immediately!