I just found out that the company head/HR who is going to be interviewing me is a former research colleague's father, and he most likely knows that I know his daughter since I have my research experience on my resume.
I decided to save myself the awkwardness and withdraw my application. I don't want to outright lie (i.e. saying that I have been hired with another company) but I also don't want to sound rude by not giving any reasons. How can I explain withdrawing my application?