Double-click 
. The Customer window opens, displaying the information for the last customer used.
Select the customer account for which you want to change the shipping address. If you need instructions, see Selecting a Customer.
Click the Shipto/Attention tab.
Any shipping information set up for this customer appears in the Shipto portion of the tab. Select the Shipto (by clicking on it) to change.
You can also search for a Shipto by clicking 
in the Shipto portion of the tab. In this dialog box, you can sort by dragging and rearranging the columns.
Once you've selected the Shipto to change, click the Zone box and enter up to three characters to create a zone for this customer. The information in this field is stored in the C-SHIPTO file. You can use this to sort reports in Report Writer.
Click the District box and enter the tax district to assign this shipping address.
Click the Tx box and type Y to specify that this customer is taxable.
to save changes.