Permanent TSB's chairman, Robert Elliot, is to step down from the board of the bank.
Mr Elliot will complete his six-year term as chairman in March of next year.
The lender said it has now begin the process of identifying a suitable replacement, supported by executive search company Odgers Berndston.
The development comes as Permanent TSB undertakes the complex process of purchasing assets from the departing Ulster Bank.
Permanent TSB has formally agreed to acquire Ulster Bank's €7 billion performing non-tracker residential mortgage book and its performing SME loan book worth €230m.
The deal also includes the entire Lombard Asset Finance loan business - worth €400m - and 25 branches in Ulster Bank's branch network.
"Noting that while it was subject to regulatory approval, the Bank’s acquisition of certain elements of Ulster Bank’s SME and Retail business will be transformative for the bank and will position us strongly for growth in the years ahead," said Mr Elliot.
"The fact that the end of my term as Chairman will coincide with the substantial conclusion of this transaction makes next year the perfect time for me to step away from the bank and allow a new Chairperson to take the reins for what will be a crucial and exciting period for the enlarged bank."