If a project rental quotation has been sent, you or the customer can decide to cancel it. In that case, mark the quotation as Canceled.
Steps
Go to Rental order management > Project rental quotations > Project rental quotations.
In the list find and selected the desired project rental quotation.
On the Action Pane, click Follow up.
Click Cancel.
In the Reason lost or canceled field, enter or select a value.
Click OK.