The Director may be a man or a woman, hence a gender-neutral language is called for.

1) For the period of the Director's vacation, business trip or other short-term absence, the General Director may appoint from among the Director's deputies a General Director Pro Tem.

2) The General Director may appoint from among the Director's deputies a General Director Pro Tem for the period of the Director's vacation, business trip or other short-term absence.


§3700.210. Absence or Disability of Director
Latest version.
The Director may select a person or position title who shall serve as Director Pro Tem in the event of absence or disability of the Director. In the event no selection has been made, the Bureau Chief with the most service time with the Agency shall serve as Director Pro Tem.
http://ilrules.elaws.us/iac/t2_pt3700_sec.3700.210

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The Director may select a person or position title who shall serve as Director Pro Tem in the event of absence or disability of the Director. In the event no selection has been made, the Bureau Chief with the most service time with the Agency shall serve as Director Pro Tem.

https://www.law.cornell.edu/regulations/illinois/Ill-Admin-C...

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If someone has a particular position or job pro tem, they have it temporarily.
https://www.collinsdictionary.com/us/dictionary/english/pro-...

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adjective for the time being
“he is the president pro tem”
synonyms:pro tempore
impermanent, temporary
not permanent; not lasting
adverb for the time being; temporarily
“"accepting pro tem that hypothesis consistent with the facts"- J.W.Krutch”
synonyms:pro tempore
https://www.vocabulary.com/dictionary/pro tem