Is there a way of converting a T to a IEnumerable without using Add or AddRange

Is there a way of converting a T to a IEnumerable without using Add or
AddRange

I have a a list of nodes:
IEnumerable<Node> list
I also have a singlular item
Node item
Is it possible to directly replace list with item without a List.Add or
List.AddRange?
list = item // do something here to convert/cast