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The required fields are: Company, Contract, Entity, and Basis.
The "Customer Order Adjustment (create)" form. The Main tab
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In the Entity field, select the legal entity of your company which is responsible for sales. The Entity field is available if the Multi-Company Accounting option is selected on the Administration > Settings > General Settings form. The default entity for all users can be selected on the Accounting >Master Data > Entities form. Also, you can specify your personal default entity, for details refer to Personal Settings.
The Basis field is filled automatically, if the adjustment to customer order has been generated based on the order. If needed, you can manually select the basis document from the list of customer documents (for this, click Show all from the drop-down list). Once the basis order is selected, click the Fill in ( 
) button to copy the data to this order. If, after you edited the adjustment, you want to cancel the edits, click the Fill in button – the details from the basis document will be copied to the adjustment.
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The currency of the customer order adjustment is defined according to the selected customer contract. To select other currency, select another contract, or create a new one, if necessary. To learn more about contracts, see Company Contracts.
Notice the hyperlink below the Basis field – AED Wholesale Price VAT Applied*Prices Include VAT* on the screenshot above (can be different in your document). By clicking the hyperlink, you can open the Prices and Currency dialog box and change the settings related to prices, discounts, and taxes applicable to the customer order adjustment. For more details, refer to The Prices and Currency dialog box.
The document totals and other information
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After filling out the tab, click the Save button to save your work. After filling out all the tabs, click Post to save and post the document without closing it or Post and close to save, post, and close the document. For other button descriptions, see Document Toolbar.
Click the Consolidated Analysis by Order link above the toolbar to run this report for the customer order being adjusted.