If the guardian of the woman stipulates a condition in the marriage contract that the authority of divorce is entitled to the woman and the husband agrees to it, then it is lawful.
If the woman puts a condition to have the right to divorce, then that is permissible and she will have the right to divorce only one time.
However, the man should not give this authority to the woman and the woman should not ask for it. Women have a greater tendency to invoke mention of divorce under emotional strain than men are, so it is not advisable for her to have the power to divorce by a mere verbal pronouncement.
After she divorces and goes through her waiting period, if they want to get back together, they may remarry with a new contract and dowry. Such a divorce will be counted as one divorce on his account in the new contract and the husband will only have two divorces remaining.
And Allah knows best.