If you need to make a proposal unavailable to the customer but keep it for your records; you can set it as Expired. This will hide the proposal content and show a notice to the customer to contact you to receive a new proposal. This can help you categorize / separate rejected proposals or prevent approval for services you no longer provide.
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To set a proposal Expired, click the down arrow menu to the right of the proposal section of a project and select "Set as Expired":

If you would like to make the proposal available to the customer again, you can Activate it from the same menu.
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