Yes, you can. If for any reason your mobile number changes, you can update this information in your Yoti app by going to Personal Details > Mobile Number > Update Mobile Number. This will allow you to add your new number and delete your existing one.
Before your new number is added, you will be sent a unique verification code which your app will then prompt you to enter. Once this is entered and confirmed, your new number will be verified and added to your Yoti account.