i do not think that would be proper accounting practice.
i guess another cash account needs to be created and an inter account transfer to the same have to be recorded. just like a clearing account in bank accounts. in case the lost money is found it can be transferred back to the original cash account.
The reason this is not the right approach is that the shortage or overage would just be moved to another asset account without resolving the accounting problem. A shortage or overage must be accounted for as an expense or income.
Create a new Expense Account if you want to report on the loss separately in your accounts.If not use on of your existing expenses accounts
Then do a payment transaction for the missing amount and select the account where the loss will be expensed - either the new account you created or an existing expense account