A short time ago, we reported that Instagram was going to add the functionality to manage multiple accounts in iOS and Android.
We should be seeing the update this week. Once launched, you will be able to go to your profile settings and add an account. Once added, you will be able to tap on your username and switch to the account you want to use.
No exact date has been mentioned, just “some time this week”. Head over to read the first post on this topic.