Alternative running scenarios for the LHCb experiment

In this report we study the possibility to collide the beams in LHCb (interaction point 8) with a modified crossing scheme which allows a transparent change of the LHCb spectrometer polarity. In the nominal scheme a polarity reversal implies significant changes to the crossing parameters and a different effective crossing angle in the collision point. The alternative scheme minimizes or avoids these effects. Emphasis is put on an evaluation of this scheme without changes to the existing hardware.