Sometimes you sit down to pray about something and find you genuinely do not know what to ask for. The situation is too tangled. You cannot tell what the good outcome even is.
Romans 8 treats not knowing what to pray as normal and already provided for. Say what is true, pray for the person rather than the outcome, and stay in the room.
Romans 8:26 speaks straight into that. It says the Spirit helps our weaknesses, because we do not know what we should pray for as we ought, but the Spirit himself makes intercession for us with groanings which cannot be uttered.
Read that again slowly. Not knowing what to pray is described in Scripture as a normal condition of the believer, and God has already made provision for it. Your inability is anticipated. It is covered.
So here is what to do when you are there.
Say what is true. Not what sounds spiritual. Start with the facts as you know them. I do not know what to ask. I do not know if I want this to end or to change. That is a real prayer and God is not startled by it.
Ask for the person, not the outcome. When you cannot see the right result, pray for the human being. Ask that they would be strengthened, comforted, given wisdom, kept. You can pray those things with confidence because Scripture is full of them.
Sit there anyway. Presence without a request is still prayer. Some of the most important praying is time spent in the room without an agenda.
And let the Spirit carry what you cannot say. That is not a poetic idea. It is the plain claim of Romans 8. There is intercession happening on your behalf that is more accurate than your own words would have been.