Kotlin basic inheritance solution

How do I make new SavingAccount with init values for owner and balance

open class BankAccount(val owner: String = "Long John Silver", private var balance: Double = 0.00) {

    constructor (amount: Double) : this() {
        this.balance = amount
    }
    fun deposit(amount: Double){
        this.balance += amount
    }
    fun withdraw(amount: Double){
        this.balance -= amount
    }
    fun getBalance(): Double{
        return this.balance
    }
}

And the child class

class SavingAccount(val increasedBy: Double = 0.05): BankAccount(){

    fun addInterest(): Unit{
        val increasedBy = (this.getBalance() * increasedBy)
        deposit(amount = increasedBy)
    }
}

and in main

fun main(args: Array<String>) {

    val sa = SavingAccount();// how to do this SavingAccount("Captain Flint", 20.00)
    println(sa.owner)
    println(sa.owner)
}

How can I create SavingAccount for a new user, without default values?