I want to create a template generating a

<ref name=abc>{{Cite something}}</ref>

reference.
However, it should also be possible to generate a 'repeat' reference:

<ref name=abc />

to cite the same source again.

When I need to create an empty tag and use

{{#tag:ref||name=abc}}

this function probably generates a new (but empty) ref tag:

<ref name=abc></ref>.

This is not what I want, obviously, and leads to errors on the page and an empty reference.