In order to change the Printer Port while Printing a Sale Bill in Marg Software, the user needs to follow the below steps:

• Go to Transactions > Sale > Modify Bill. 

• A 'Modify' window will appear in which the user will select the options as per the requirement i.e. bill no, bill date, etc.

• A 'Sale As On' window will appear. Press 'Enter' on the selected entry which the user needs to print.

• A 'Sale Alteration' window will appear.

• Click on the 'Print' tab to print the selected bill.

• Now the user will press 'F3' key on the printing window.

• A 'Printing Port' window will appear. Press 'Enter' key twice.

• In 'Printer Port', the user will select the 'Port' as per the requirement.

• Then press 'Enter' key twice. 

• Suppose select 'LPT2-Microsoft Xp Document Writer'. 

After following the above steps, the selected bill will get printed according to the selected printer port.