as salam alaikum
if a person find him/herself in a work environment with people of the opposite gender, because he/she doesn't find another job or any other reason, he/she should keep all the rules etiquettes that preserve his/her haya' and try to avoid extra-professional conversations. There is nothing wrong in sending greetings and work-related talk as long as they don't lead to haram consequences. Obviously one should strive also to be gentle, efficient and helpful in every circumstance. However "warm and friendly interactions" are not a necessity and should be avoided.
With prayers for your success.