Angel Robe Pattern?

I'm in charge of our church Christmas Program. It's a very small church and in the past I've never had costumed people in the program. This year is just a wee bit different as I'll have 2 angels. All I want to do is have them in a white "choir robe" of sorts. Nothing elaborate..no wings, halos or anything like that. Just a white robe. I'm very willing to make it but I can't find a pattern. Yes I considered something like a bathrobe but every pattern I've seen had a tie around the waist. I'd prefer something for over the head or zippered up the front...something like a choir robe. I also considered trying to make one from satin bedsheets. I don't suppose anyone has something I could copy, borrow, or purchase?

Thank you!!