I am in over $13 million debt, great for a brand new player

I kinda get how it all works now... lol. I am selling one of my Boeing 757-200 to recoup costs and will be looking for a cheaper gate option than what I am currently raking in debt from a $300,000 month gate at Charles de Gaule, no brainer... a $300,000 monthly lease compared to a $93,000 revenue after expences paid! so I will have to find a cheaper location for a while, So back to my main question, How can I return an aircraft I leased?