Working in Update and Confirm Modes 
Use the Update and Confirm (the OK command button) modes to make necessary changes in SAP Business One and to save those changes to the database. You can change business partner or employee information, sales or purchasing documents, and item or payment details.
SAP Business One shifts to the Update mode when you make a change to the current window. The OK command button becomes Update. Information that you cannot update is disabled.
Use the following example to change the customer record you added in Working in the Add Mode.
Procedure
Choose
Business Partners 
Business Partner Master Data 
.The Business Partner Master Data window opens in the Find mode.
Find a customer you created earlier, as described in Working in the Find Mode.
Change the customer’s currency and update the contact person’s details.
Choose Update to update the record and save it to the database.
SAP Business One shifts to the Confirm mode.
Choose OK to confirm the action and close the window.