Regarding this issue, Sheikh Ahmad Kutty, an Islamic scholar, says:
Marriage in Islam is primarily intended to protect the person’s chastity by guarding against fornication, and thus, enable each other to build the foundations of a happy family. These principles are only fulfilled when the parties enter into marriage with full consent, of their own accord, without any external pressure.
It is, therefore, important for people to choose marriage partners who have good character, moral integrity and faith. The role of parents in the marriage of their children is limited. They are only to ensure that the latter makes the right choice. The Prophet (peace and blessings be upon him) said, “If a person of pleasing character and faith comes forward as a suitor, accept him/her; otherwise, you are opening the door to corruption.” Therefore, it is imperative that parents agree to marriage once these criteria have been fulfilled.
Therefore, if the father of a particular lady refuses a person of her choice who is of good character and faith for no justifiable reasons according to Islam, such a lady should try to approach her father again either by herself or through wise people in the community he trusts in order to urge him to change his mind.
If, after several efforts, he persists in his refusal, the lady has the right to marry the person she chooses. In this case she should ask the next closest male relative to give her hand in marriage on her behalf. If no one is willing to do so, she is free to delegate someone as her representative and get married. Marriage performed in this way under the above circumstances is considered perfectly valid in Islam.
Having said this, it should be noted that obedience to her parents and maintaining good relations with them should not be neglected.