You can simply not change your currency if it is dollars, euros, or even pounds (if your currency is the crown, for example, or another currency, you can exchange it for one of the previous currencies because it is easier to exchange).
And do not exchange it for the Egyptian pound except when necessary while you are in Egypt, where you can easily exchange it for the Egyptian pound from any ATM or you can exchange it at the hotel or with anyone. In this case, use Google to know the real value of the Egyptian pound to avoid being scammed.