Exhibit 99.A

Joint Filing Agreement

The undersigned hereby agree that the statement on Schedule 13G/A with respect to the Common Stock, $0.01 par value of Envision Healthcare Corporation, dated as of February 14, 2019, is, and any amendments thereto (including amendments on Schedule 13D) signed by each of the undersigned shall be, filed on behalf of each of us pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Securities Exchange Act of 1934.

Date: February 14, 2019

MAVERICK CAPITAL, LTD.
By:	Maverick Capital Management, LLC
	Its General Partner
	By:	Lee S. Ainslie III, Manager
		By:	/s/ Mark Gurevich
			Mark Gurevich
			Under Power of Attorney dated
			March 15, 2018

MAVERICK CAPITAL MANAGEMENT, LLC
By:	Lee S. Ainslie III, Manager
	By:	/s/ Mark Gurevich
		Mark Gurevich
		Under Power of Attorney dated
		March 15, 2018

LEE S. AINSLIE III
By:	/s/ Mark Gurevich
	Mark Gurevich
	Under Power of Attorney dated
	March 15, 2018

ANDREW H. WARFORD
By:	/s/ Mark Gurevich
	Mark Gurevich
	Under Power of Attorney dated
	March 16, 2018