Dought & clear, - Can khulwah be avoided if another woman is present?.

My wife told me that a gas canister ran out at home and has to be
changed, but I am not at home. Can a worker come to install the gas
canisters at home when I am not present? Please note that there is
another sister who will be with my wife in the house so as to avoid
leaving her on her own with the worker.
Praise be to Allah.
Firstly:
The scholars (may Allah have mercy on them) are unanimously agreed
that it is haraam to be alone with a non-mahram woman (khulwah),
because of the saheeh hadeeth: "No man should be alone with a woman
unless there is a mahram with her." Narrated by al-Bukhaari, 5233;
Muslim, 1341.
An-Nawawi (may Allah have mercy on him) said: If a non-mahram man is
alone with a non-mahram woman, with no third person present, this is
haraam according to scholarly consensus.
End quote fromSharh Saheeh Muslim, 9/109
As-San'aani (may Allah have mercy on him) said: This hadeeth indicates
that it is haraam to be alone with a non-mahram woman, and there is
consensus on this point.
End quote fromSubul as-Salaam. 1/608
Secondly:
There is nothing wrong with a woman allowing a non-mahram man to enter
her husband's house when he is absent, as long as two conditions are
met:
1.Her husband should have given her permission to do that
2.There should be no khulwah (i.e., she should not be alone with him);
rather there should be a mahram with her such as her father or
brother, or anyone for whom it is permanently forbidden to marry her.
If she does not have a mahram with her, but there is another woman
with her, khulwah may be avoided thereby, but it is not permissible
for a woman to put herself in that situation unless the woman is
trustworthy and the man who is with them in that place is also
trustworthy and there is no fear that he could overpower the two
women.
An-Nawawi (may Allah have mercy on him) said: If a non-mahram man is
alone with a non-mahram woman, without a third person being present
with them, this is haraam according to scholarly consensus; this is
different from if a man is with a number of non-mahram women, in which
case the correct view is that it is permissible.
End quote fromSharh Saheeh Muslim, 9/109
As-San'aani (may Allah have mercy on him) said: It says in the hadeeth
that "the third one present with them is the Shaytaan". Can someone
other than the mahram take his place in that regard, so that there
will be someone with them in order that khulwah will be avoided? It
seems to be the case that he may take his place, because the reason
for the prohibition is the fear that the Shaytaan may cause temptation
between them.
End quote fromSubul as-Salaam, 1/608
Based on that, there is nothing wrong with the man allowing a
non-mahram to enter his house, on condition that he is not alone with
his wife and that he is trustworthy. However the basic principle, and
the best precaution to safeguard religious commitment, is that he
should not allow that unless there is a mahram present.
And Allah knows best.