Does Istikhara (guidance-seeking prayer) nullify the role of reason in taking means and relying upon Allah, or is it used to facilitate good and avert evil regardless of one's feeling of ease or unease?

Istikhara is a Muslim's request to his Lord to choose for him what is best for him in his religion and worldly life. It is a Sunnah when embarking on any important matter. It is performed by praying two rak'ahs other than the obligatory prayers, then the Muslim recites the du'a (supplication) narrated from the Prophet, peace and blessings be upon him, which begins with: "O Allah, I seek Your guidance by Your knowledge..." After the du'a, one takes the necessary means and proceeds with what their heart is content with, for that is what Allah has chosen for them.