My friend is using other passport because that time she is still young travelling and looking for a job to other countries, so to increase her age she use other person passport and her eye was scanned in Dubai immigration.Now she wants to come back in Dubai with her own passport. How to delete previous eye scan record in immigration?

You don't , in fact she will be in trouble for committing fraud. Which is what she did using a false Identity. That's a crime in most if not every country in the world. And she WILL be caught if she goes back to dubai

No other way to clear that record?

No... this is EXACTLY the reason they do this, and why they NEVER erase them... to catch people who use false ID's, because eventually they get caught. And Most people that do it, do it to break the law for any number of reasons. Some for fairly minor reasons... others very serious. People that do it once, usually do it many more times. Once that line is crossed, its very easy to do it again.

You can fake a document... you can't fake an eye scan.