"The terms and conditions of margin accounts vary but, generally speaking, you shouldn't expect to have the ability to set up payment plans or negotiate the terms of your debt. Your brokerage can legally change key terms at any time, such as how much equity you need to maintain.3 When you're required to add cash or securities to your account, it's known as a margin call. If you can't swiftly deposit the cash or stocks to cover the margin call, the brokerage can sell securities within your account at its discretion."

What You Need to Know About Margin Trading (thebalance.com)