If a client declines to proceed with your quote, you can mark the quote as declined in WorkGuru.  This archived the quote and its status 

To decline a quote, click on the quote number from the issued tab of the quotes dashboard.

From the functionality at the base of the quote, click the Decline Quote button.

WorkGuru will then prompt for a note to capture the reason the client declined.  

This note is available in the WorkGuru's sales reports for further analysis on sales performance usually when looking at quotes with the declined status vs accepted.  The available pivot field is called: DECLINETEXT

The quote status is also updated to declined and will be archived in the Declined tab of the quotes dashboard.