The relevant section is §97.119 Station identification. The call of the
station must be used, "an indicator
consisting of the call sign assigned to the control operator's station must
be included after the call sign."

However, I don't think the FCC prohibits one amateur from lending his
equipment to another. So
you could take the position that the station owner has lent his equipment to
you, and during the loan,
it is your station, so you only have to use your call sign.

"KC4UAI" wrote in message
...
... I use my assigned call sign to ID myself when operating my station,
but what if I'm operating a station that's not mine? Can I just
provide my call as identification or do I need to include the
station's call too?...