PART NUMBER: IIf([MANUFACTOR SENT]=2,[GE PART #]),IIf([MANUFACTOR SENT]=3,[PHILLIPS PART #]),IIf([MANUFACTOR SENT]=1,[SYLVANIA PART #],"IfFalse"))
That might work.......
You might look into using an "If....Then" or "Select Case" statement. With those you could also add a message box if number was not 1,2, or 3.