Close Opportunity Dialog Box
When you are no longer actively pursuing an opportunity (for example, when you have been awarded the contract), use the Close Opportunity dialog box to close it.
Closing an opportunity does not delete it, but its status is set to Inactive. It is no longer included in the selection lists of active opportunities, and you can no longer edit any of the information related to it.
If you close an opportunity and later need to open it again (for example, if you decide to renew your pursuit of the opportunity or you want to edit some of the opportunity information), select the opportunity, and click on the Opportunities toolbar. (Make sure you select All in the filter list for the search field so that the search includes inactive opportunities.)