Hi Abirami,
Here's the help topic from PowerPoint help:
• Multiple masters
•
You can use more than one master (slide and title masters) in a
presentation by applying a new design template to a selection of slides
or by adding slides from another presentation that uses a different
design template. When you copy slides from one presentation to another,
you can choose to retain the design template of those slides or use the
design template of the presentation you are copying them
Based on that information I think you would be best to use slide sorter
view to select the slides you wish to apply the alternative design
template to. Then select a different design template from the formatting
palette or design toolbar button.
-Jim
