If you have a sphere that is not covered by any active Immortal, I would recommend one of two things.

One, you can seek out an existing Immortal with alignment or beliefs similar to your own, and request them to intervene for you.

Two, you can seek out some sort of divine being that you've created out of your own imagination that embodies your sphere, and pray to that being from an appropriate place. This is a bit harder, since you'd have to convince one of us at random to come empower you, playing the part of that lesser deity, but it's not impossible and has happened many times before.

Hope that helps.