Wire transfer to my sister in foreign country

I'm leaving U.S for good, after couple of years and need to sort out my money. If I wire transfer my money to my sister bank account in my coutry, how can I avoid paying taxes since I have already paid all the tax. (The money was income from working) Any form I need to fill out? Unless there's different way to take my money to my coutry? I don't have a foreign bank account, and don't want IRS to think this is a gift since I'm transferring it to my sister? Thank you