April 23, 2010

	

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	Exhibit 10.4

	
	Trinseo PLC
76 Sir John Rogerson’s Quay
Dublin 2 
D02 FX51, Ireland

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May 9, 2022
Andre Lanning
S.V.P., Chief Commercial Officer
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Dear Andre, 
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We are pleased to confirm a change in your Change of Control benefit under your employment contract with Trinseo PLC or its affiliate.  Basically, the change increases the severance amount from 18 months to 24 months provided all other conditions of this benefit are met.  More particularly, please note that the double trigger elements both still apply.
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A side-by-side comparison of the change is provided below:
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	Current Change in Control Severance - Section 7(d)
	New Change in Control Severance - Section 7(d)

	(i)(i)          This Section 7(d) shall apply if the Executive's employment by the Company is terminated (x) by the Company other than for Cause, or (y) by the Executive for good reason as defined in art. 340c para 2 CO, in either case, during the two (2)-year period commencing upon a Change in Control. Subject to the Executive's not engaging in a Material Covenant Violation or a Material Cooperation Violation, upon a termination described in the preceding sentence, the Executive shall receive the benefits set forth in Section 7(c) hereof, except that in lieu of receiving the Severance Amount in installments as contemplated under Section 7(c)(ii) hereof, the Executive shall receive a lump sum payment equal to the Severance Amount on the date of such termination.
	(i)This Section 7(d) shall apply if the Executive's employment by the Company is terminated (x) by the Company other than for Cause, or (y) by the Executive for good reason as defined in art. 340c para 2 CO, in either case, during the two (2)-year period commencing upon a Change in Control.   Subject to the Executive's not engaging in a Material Covenant Violation or a Material Cooperation Violation, upon a termination described in the preceding sentence, the Executive shall receive thebenefits set forth in Section 7(c) hereof, except that (i) the Severance Amount shall be two (2.0) multiplied by the annual sum of the Executive’s Base Salary and Target Bonus in effect for the then-current year of termination, and (ii)  in lieu of receiving the Severance Amount in installments as contemplated under Section 7(c)(ii) hereof, the Executive shall receive a lump sum payment equal to the Severance Amount on the date of such termination. 
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By way of this letter amendment, we propose deleting current Section 7(d)(i) and replacing it with new Section 7(d)(i). There are no other changes to your employment contract.  All other terms and conditions remain unchanged. 
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Please return your acceptance at your earliest convenience.
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Best regards,
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	Signature:  /s/ Frank A. Bozich
	Signature:  /s/ Paula Cooney

	Name:Frank A. Bozich
	Name:Paula Cooney

	Title:President & Chief Executive Officer
	Title:S.V.P., Chief Human Resources Officer

	Date:5-20-2022
	Date:5-20-2022



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	Trinseo PLC
76 Sir John Rogerson’s Quay
Dublin 2 
D02 FX51, Ireland

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I have read this letter amendment, understand it, and agree to the terms set forth above:
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Date: 5/23/2022Signature: /s/ Andre Lanning
Andre Lanning

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