Rescheduling a phone interview?

Not to be too specific, but I currently work unusual and generally flexible hours. I scheduled a phone interview with a recruiter for this upcoming Monday, but something has been scheduled at my current job that would require me to be occupied at the time I scheduled the interview.

So my question is, how bad of an idea is it to ask to reschedule the interview? I checked the original calendar invite and there seems to be availability in the following days.

usa jobs
usa jobs resume
usa hotel jobs
usajobs
usa jobs federal government
usa job in ksa
usa jobs
usa jobs login
usa jobs gov
usajobs.gov
www.usajobs.gov
usajobs.com
usajobs
usajobs.gov official