Medical Do I have to accept changes to role I accepted?

[tantacles]

Accepted an outpatient position offer at a hospital part time. After the fact, I have been ‘asked’ by director to take on a day of ER coverage as the prior attending wants to be outpatient as well. They were aware of other outside obligations I had from the beginning. As a new employee do I have to accept this ? I have been receiving a lot of pressure from them.

As a new employee, you are not obligated to accept this, but if you do not, they have the option to say, "Sorry. You're fired."