Resizing a pdf file within Adobe Acrobat Reader..?

You know, when someone is not familiar with how to work with certain things- it makes them feel stupid, or at least reveals the ignorance of the process... I have had an artist create a company logo for me... But now as I try to go and get the logo added to a business card, the website that I am using to get that done says the file is too big... So, can anyone here help me resize this file to an A4, 300dpi  sized file? I sure do appreciate any help! I have downloaded the free trial of the Adboe Acrobat Reader DC... Unfortunatelyy, I will need step by step instructions.. Thanks again!!