Actually, Angelic evocation is a thing and can be done. I do not also see it as rude as you are petitioning them to appear, not forcing them- the idea that evocation/summoning is offensive or rude originated a couple of years ago on this site- I would guess from people who have not really practiced evocation!
Anyone who practices the LBRP technically evokes Uriel every time!
You can modify the goetia rituals to fit with evoking an angel- you can, and I believe should, reword the rite to make it more polite.
The process is simple. Invoke divine energy into yourelf, affirm you are the god of your universe (your temple and self), Use your authority to cal up te being, make it be present, ask it questions, give thanks, banish- write up results. Hey presto, you have an evocation.