DOUBLING, RE-DOUBLING, ETC.
The effect of doubling, re-doubling, and so on, is that the value of each trick above six is doubled, quadrupled, and so on.
After the trump declaration has been made by the dealer or his partner, their adversaries have the right to double. The eldest hand has the first right. If he does not wish to double, he may ask his partner, "May I lead?" His partner shall answer, "Yes," or "I double."
If either of their adversaries elect to double, the dealer and his partner have the right to re-double. The player who has declared the trump shall have the first right. He may say, "I re-double" or "Satisfied." Should he say the latter, his partner may re-double.
If the dealer or his partner elect to re-double, their adversaries shall have the right to again double. The original doubler has the first right.
If the right-hand adversary of the dealer double before his partner has asked "May I lead?" the declarer of the trump shall have the right to say whether or not the double shall stand. If he decide that the double shall stand, the process of re-doubling may continue as described above.