Use of "X" for "first round" of interviews

Bonjour tout le monde!

So we now have two postings up; although the second is a French posting.
Being francophone, this second posting raised a question: If I applied to this second posting, but it was not what I wanted at the end of the day, would I have no choice but to rank it 2 at the end of first interview round as I only have two interviews (let's say); or would I be able to use 1 "X" during our particular process? Did I have that option in our delayed exceptional process?

According to Danielle Délorme, the answer is yes. I was told today that we will have the opportunity to use one and only one X in our first round ranking (March 22nd). After that though, there will be no X.

Thought it was important to explicit.
Céline.