How to download and re-upload an application on iTunes Connection?

Question

iOS

I was instructed to re-upload the application to the iTunes connection. There are 2 paid iOs developer accounts: one for physical. person, another in jur. face. The first account has a published application, you need to download its repository, slightly change the name and upload this application to the second account. I've never dealt with iOS before. Please tell me what I need to do the above steps, preferably step by step :) but, can you link to some article or guide, and do I also need XCode, can I do my plan using only Windows, etc.?