If she wants the hen removed...
If she's got a cat/dog carrier that is secure, if she puts a trail of cooked sweetcorn from near the bird to the *inside* of the dog/cat carrier (which has been strategically placed somewhere where she can keep and eye on it and close the door easily when the bird goes in the carrier), with a pile of the sweetcorn in the carrier. Chickens *adore* sweetcorn to the point of ecstacy and it won't be long before the chicken follows the trail...
Apart from that, hens are 'in' at the moment so the fact she's got a hen loose shouldn't detract from someone visiting.
In the longer term - if it was my hen - I'd be getting it back and making sure that where it is supposed to be is secure. If a hen can get out, a fox/mink/dog/rat.. can get in and all of those will attack, kill and eat hens given the chance. And in any event, it's not the sign of a good neighbour if they let their hens get out like that.