There is no way to undo deleting an eQuote, once it is gone, it is gone. You can always re-create it, of course, but if you have sent eQuotes requests from the eQuote you deleted, they cannot be imported into the Bid. If you attempt to delete an eQuote that was already sent, you will receive a notification asking if this is what you really want to do - think twice before deleting.
If you delete an eQuote after accepting/award it to a Supplier, the assigned Supplier is removed from the Materials grid, but the accepted pricing remains. If you want, you can use the 'Refresh Material Cost...' option, explained in Related Articles, to restore original pricing.
Adding and Removing Items from an eQuote