How do I create a professional relationship with my estranged sister/new co-worker?

My sister is a year older than me (26f) and we never really had a massive issue, but we were close as kids, then we grew up, developed our own personalities, and found that we just didn't like each other. We put up with it because we're family, but time went on and we grew even further apart and had a few problems, ranging from sarcastic comments to mid level arguments, and eventually I realised that as I didn't like her, I didn't have to speak to her, so I didn't.

I stopped speaking to her about 4 years ago, shortly after one of our bigger arguments, which is around the time I started working at my current workplace. She is now also working here. I'm sure it's just coincidence but it's a little weird for me, because she's only been here a few weeks but is telling people that she's my sister and she's acting like we're close and asking me to meet her outside of work to catch up, among other things. She's not in my team at work, as she's in a different field to me, so I do get some reprieve from her, but part of my job is communicating with other teams and we share a building and common areas, and our coworkers overlap, so I do need to be professional with her.

I am trying very hard to be professional, but it's odd for me to have to work with my sister, and odder still when she wants to act like sisters despite us only seeing each other a few times in as many years. I'm uncomfortable and embarrassed, but this isn't something I can tell a manager about because it's just my sister wanting to act like my sister which they'll tell me is completely reasonable. I also can't be overly hostile or cold to her because it's a professional environment.

How do I make clear that I only want a professional relationship with her, within working hours, and not whatever it is that she's angling for, and how can I reasonably maintain this?

TL;DR! The sister I don't speak to got a job at my workplace and now wants to act like sisters. How do I keep things professional?

Submitted November 02, 2021 at 03:42AM by throwRAhelpsis https://ift.tt/3bAhLkE