Adding Standard Size(4:3) PPT to Widescreen Size(16:9) Cover Page

I have one cover page ppt (having the widescreen size), which needs to combine with another ppt (having standard size).

Appending both ppt is converting standard size to widescreen with the portion of the right side as blank.

Let me know the way in which I can handle this case. Do I need to have a different size cover page ???. Or Can I convert the cover page slide size dynamically to the main slide size ???

Please find the screenshot attached herewithcombined slides.jpg (92.5 KB)
original slide.png (22.7 KB)
.

@MINDNOIDA,
Thank for the issue description. Could you also share the presentation samples and a code example for investigation, please?

Input PPT is in Document/Files/TestDoc.docx folder in the project directory.
Input PPT with undesired behavior is in Document/Destination/CombinedDoc.docx folder in the project directory.
Input PPT with desired behavior is in Document/Expected/ExpectedDoc.docx folder in the project directory.

I am attaching the standalone application with the readme file for further instructions.
TestApplication.zip (448.9 KB)

@MINDNOIDA,
Please consider the next way to combine presentations with different slide sizes:

var slideSize = presentation1.SlideSize.Size;
presentation2.SlideSize.SetSize(slideSize.Width, slideSize.Height, SlideSizeScaleType.EnsureFit);

API Reference: ISlideSize Interface

Important: I removed your license file from the attached zip file. Please send the license files as a private message in the future.