Here are the simple steps to follow:
1) Login to your Tata sky account with your registered phone number or Subscripton ID.
2) In the main menu bar, there is this View/Modify Packages Option.
3) Click on that.
4) They will ask you for the password once more,
5) Enter the password, and you will be taken to the relevant page.
6) There you will find options to view and add Base Pack, Regional Packs, Add-On Packs, Actve Packs, Specials, A-La-Carte
7) They would show the existing pack you are using and you would get to see options of each pack with the view option to see the channels they include.
8) Click or select the one of your choice from the list and click on the "submit" button on the right side of the page.
9) They will redirect the page of processing in few seconds and then ask for confirmation.
10) Click Confirm and you are done.