Acting President of Turkey
The acting president of Turkey () is a temporary post provided by the Constitution of Turkey. The acting president is a person who fulfills the duties and powers of the president of Turkey when cases of incapacity and vacancy occur. In cases where the President of Turkey temporarily leaves his office due to illness or going abroad, the oldest Vice President of Turkey shall act for the President and exercise the powers of the President. If the office of the President becomes vacant, the Presidential election is held within 45 days. Until a new one is elected, the Vice President acts as the President and exercises the powers of the President. History
Prior to the 2017 Turkish constitutional referendum, the role of acting president was given to the Speaker of the Grand National Assembly of Turkey. Following the outcome of the referendum, the relevant article in the constitution was changed from the Speaker to the Vice President of Turkey. Constitutional provisions on acting Presidency
Article 106, Chapter 2:
If the presidential office becomes vacant for any reason, the presidential election shall be held within forty-five days. The Deputy President of the Republic of Turkey shall act as and exercise the powers of the President of the Republic until the next President of the Republic is elected. If one year or less remains for the general election, the election for the Grand National Assembly of Turkey shall be renewed together with the presidential election. If more than one year remains for the general election, the President of the Republic of Turkey shall continue to serve until the election date of the Grand National Assembly of Turkey. In cases where the President of the Republic is temporarily absent from his/her duties on account of illness or travelling abroad, the deputy president acts as the President of the Republic and exercises his/her powers. List
The following politicians served as acting presidents. References

 
Presidency of Turkey