You may want to suggest a "system" to your staffing office, such that they have a list of people who voluntarily want to be "called off" on that shift - first come first served; people on this list are called in order after all people scheduled to work "extra shifts" (i.e., over and above their contracted number of hours). Then, if still more staff have to be called off, the staffing office calls those who work per diem (being called off when one is per diem is not unusual) and then finally they call off scheduled staff depending upon whose turn it is.
You can inform the staffing office if you do not mind being called off, even if you haven't officially put your name on the list or you can put your name on the list - either way you are helping the hospital and your colleagues, because you are in a fortunate financial position - many RNs are their family's main or only breadwinner, and losing a shift to call off makes an impact on their budget.
Opting to be called off or accepting call off is not viewed negatively. However, at times of high census be prepared to take an extra shift if necessary! Staffing is all about staff being flexible...
