the meeting’s permanent Chairman, or the meeting's final chairman, or the chairman elected for the assembly, or the President appointed for the meeting

See:

https://www.google.co.uk/?gws_rd=ssl#q="the meeting's p...

4 Dec 2013 - Georgios Braimis of Pericles as the Meeting's final chairman and Mr. Dimitrios P. Malamos as the final Secretary and as ballot counter, with ...
http://www.thracegroup.com/uploads_file/2013/12/04/p18auv7k8...’

The chairman elected for the assembly hosted the meeting. Agendas for the assembly, as per the organization's constitution, were as follows: 1. Election of ...
http://www.hatemalo.dk/107919068

The President appointed for the meeting of a Committee on Resolutions comprised of. Terry L.Erwin, chair, R.Duncan Carter and. Maurice J. Tauber, and asked ...
https://oup.silverchair-cdn.com/oup/backfile/Content_public/...


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Note added at 12 hrs (2017-05-30 06:03:28 GMT)
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Sorry, the first reference above should have been:

https://www.google.co.uk/?gws_rd=ssl#q="the meeting's p...


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Note added at 13 hrs (2017-05-30 06:11:04 GMT)
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Since my first reference is not showing clearly, write:

"the meeting's permanent Chairman"

(with the inverted commas) in the Google search box.

Otherwise, see:

28 Jul 2015 - According to Cheras Wanita chief Datuk Zurainah Musa, the meeting's permanent chairman had, at the start of the AGM, asked delegates not to ...
http://www.thestar.com.my/opinion/columnists/analysis/2015/0...

28 Apr 2001 - The meeting's permanent chairman Razali Hanafiah, instead of casting his vote to determine the winner, decided to leave it to the Kedah state ...
http://ww1.utusan.com.my/utusan/info.asp?y=2001&dt=0428&pub=...

... ovation, which, was duplicated when Mrs. William H Good, national committeeman, who served as the meeting's permanent chairman, presented him. Waves ...
https://www.newspapers.com/newspage/52755923/


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Note added at 13 hrs (2017-05-30 06:14:02 GMT)
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I prefer the first two of the alternatives that I have given.

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Note added at 16 hrs (2017-05-30 09:28:37 GMT)
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If your text is referring to an annual general meeting of a company or corporation, although the Greek says, “the meeting’s final (or permanent) Chairman”, I think that it is safe to translate this as, “the Chairman elected (or appointed) by the meeting”, because a chairman appointed by a general meeting would be ‘final’ or ‘permanent’, not only for the meeting itself, but probably also for the whole of the next twelve months, until his appointment is reconfirmed by a subsequent annual general meeting.

See:

29 Dec 2009 - comment or observation of members. Confirmation of minutes. 32. The President or the chairman elected by the meeting, as the case may be, ...
http://www.justiceservices.gov.mt/DownloadDocument.aspx?app=...

All district meetings shall be presided over by the chairman elected by the meeting, who shall decide all matters and things pertaining to the transaction of ...
http://www.besog1.arlafoods.dk/appl/HJ/HJ201AFD/HJ201CFG.NSF...$FILE/Articles_of_Association_UK_140508.pdf

The Chairman of the Group as appointed by the Board, or, in his absence, the. Senior Independent Director or the Chairman appointed by the meeting. Members.
http://www.rbs.com/content/dam/rbs/Documents/about/boards-co...

I have now given you a number of equally suitable alternative ways of translating your text and it’s up to you to choose which you prefer.