How to Install the app twice without interference in android?

I have an Android app (let's called X), I want to create a second app X2 but based on the other app. So I changed the manifest application name property to X2 also I changed the package name...but still when I install X2, app X is erased!

What properties should I change so I can install the two app independently on one devices. I'm working on eclispe.

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.company.app1"
    android:versionCode="1"
    android:versionName="1.0" >

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name1"
        android:theme="@style/AppTheme" >

after change.

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.company.app2"
android:versionCode="1"
android:versionName="1.0" >

<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name2"
    android:theme="@style/AppTheme" >

Solution

Well it worked on other device with more recent platform ! Anyway the proper response will be you just have to change the name and the package of the application.

EDIT 1: Now if you are using Android Studio use applicationIdSuffix to have one app for each flavor.

debug {
        applicationIdSuffix ".debug"
    }