Falcon 10/100
Air Traffic Control Fully Certified
Communication Breakdown; Situational Awareness
ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued New Clearance
Human Factors; Procedure
While working (2) Sectors combined; Aircraft Y and Aircraft Z were conducting air-refueling in ABCDE.  This track is normally left turns; Aircraft Y asked to manuever in the track airspace to accomodate the receiver due to the sun angle.  I gave the aircraft permission to manuever; at the normal turn point where the aircraft would turn left the refuelers made a right turn into Aircraft X who was on a 20 degree left vector to avoid the turn point. Upon noticing the right turn I turned Aircraft X an additional 20 left and asked the tanker for a tighter turn to the right.  These instructions proved to be insufficient to maintain the required separation.  I would have pinned down the tanker more as to how he wanted to manuever.
Enroute Controller described a probable loss of separation event during a military re-fueling exercise when maneuvering intentions by the tanker were not clarified.