What do you do when an employee puts her social life before work? It is hard to make an employee do something outside of normal hours, but when it comes to big events, you should expect your employees to pull their weight. When they don't, the problem isn't about the night they don't show up, it is about the connection they feel with the company. The employee should want to be there to support her team and the company, but should also know ahead of time what exactly is expected of her.
Here are some tips when having this discussion with an employee:
Set clear expectations on what is expected of the employee for each event and project.
Make it her decision, but remind her why she would be an asset at the event
Remind the employee the impact her decision has on the rest of the team and the business.
Put the responsibility on her to prepare the team in her absence.
Have a follow up conversation. Don't leave anything hanging.