WACC Question

Company X is considering changing its capital structure, in light of the tough business environment. 
Currently, Company X’s total capital consists of: 
$950 million in debt 
$20 million in leased assets 
$500 million of preferred stock 
$900 million in common stock 
$750 million in retained earnings 

The debt coupon is 8% and tax rate is 40% while the current preferred share price is $96.20 and the dividends per share is $9. 
The company's common stock is trading at $25.50, it's dividend payout this year is $1.15 the growth rate of the dividend is 8.5%. 

Leases are at an average cost of 8%. 
b. If Company X wants to change its capital structure (i.e., lower their WACC), what should it do?