Exhibit 10.4
SemManagement L.L.C.
Waiver And Release
Agreement

    This agreement, waiver and release (this “Agreement”), made as of the 2nd
day of August, 2017, is made by and among SemManagement L.L.C. (together with
all successors thereto, “Company”) and Candice L. Cheeseman (“Employee”).
WHEREAS, Employee received Restricted Stock Awards (the “RSAs”) under the
SemGroup Corporation Equity Incentive Plan that vest pursuant to the terms of
Award Agreements (the “Award Agreements”) on March 2, 2018 and March 1, 2019
(the “Vesting Dates”);

WHEREAS, Section 3(e) of the Award Agreements provides that the Equity Awards
related thereto together with associated dividends will be forfeited by the
Employee without any consideration if the Employee’s service is terminated other
than in connection with a change of control, death, disability, or involuntary
termination of service without cause;

WHEREAS, on February 24, 2011, the Compensation Committee of the Board of
Directors of SemGroup Corporation (the “Compensation Committee”) adopted a
cash-based Short-Term Incentive Program (the “STIP”);
WHEREAS, the Compensation Committee previously established the Employee’s target
award, performance measures, and personal performance goals for the STIP
performance year ending December 31, 2017 (the “2017 Performance Year”);
WHEREAS, the Employee has notified the Company of her intention to retire prior
to the end of the 2017 Performance Year and the Vesting Dates; and
WHEREAS, notwithstanding the Employee’s retirement and subject to the
effectiveness of this Agreement, the Compensation Committee approved (i) the
designation of the Employee as an “Eligible Employee” under the STIP with
respect to the 2017 Performance Year to be eligible to receive a STIP award
pro-rated for the period of 2017 during which the Employee was an employee of
the Company (“Pro-Rated STIP Eligibility”) and (ii) the vesting of the RSAs and
associated dividends (the “Modified Vesting”).

NOW THEREFORE, in consideration of Pro-Rated STIP Eligibility and the Modified
Vesting and in consideration of the representations, covenants and mutual
promises set forth in this Agreement, the parties agree as follows:

1.    Termination. The parties have agreed that the at-will employment
relationship between Employee and the Company is wholly and completely
terminated in all respects, effective August 1, 2017 (the “Retirement Date”).
2.    STIP Payment and Modified Vesting. In consideration of the
representations, agreements, waivers, and releases set forth herein, and upon
the terms and conditions herein described, the Employee will qualify for
Pro-Rated STIP Eligibility and the Company will consummate the Modified Vesting.
Employee understands and represents that Pro-Rated STIP Eligibility and the
Modified Vesting constitute consideration to which she would not otherwise be
entitled but for this Agreement. Employee acknowledges

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that Pro-Rated STIP Eligibility may not result in an award or may result in an
award significantly less than Employee’s pro-rated target award for the 2017
Performance Year and agrees that, in such event, the Modified Vesting by itself
is sufficient consideration for the representations, covenants and mutual
promises set forth in this Agreement.
3.    Time of Offer and Effectiveness. The offer of Pro-Rated STIP Eligibility
and the Modified Vesting shall be open until the close of business twenty-one
(21) calendar days from the Retirement Date. Pro-Rated STIP Eligibility and
consummation of the Modified Vesting shall be subject to effectiveness of this
Agreement and shall occur on the Effective Date as described in Section 8.
Pro-Rated STIP Eligibility and any award with respect thereto shall be subject
to the terms and provisions of the STIP.
4.    Release (“Release”). Except with respect to Pro-Rated STIP Eligibility and
the Modified Vesting, the Employee, and Employee’s heirs, executors, assigns,
agents, legal representatives, and personal representatives, hereby releases,
acquits and forever discharges the Company, its agents, subsidiaries,
affiliates, operating units and their respective officers, directors, agents,
servants, employees, attorneys, stockholders, successors, assigns and
affiliates, of and from any and all claims, liabilities, demands, obligations,
promises, acts, agreements, causes of action, costs, expenses, attorneys fees,
damages, indemnities and obligations of every kind and nature, in law, equity,
or otherwise, known and unknown, suspected and unsuspected, disclosed and
undisclosed, arising out of or in any way related to agreements, events, acts or
conduct at any time prior to the day prior to execution of this Agreement that
arose out of or were related to the Employee’s employment with the Company or
the Employee’s termination of employment with the Company including, but not
limited to, any and all claims or demands pursuant to Title VII of the Civil
Rights Act of 1964 as amended by the Civil Rights Act of 1991, which prohibits
discrimination in employment based on race, color, national origin, religion or
sex; the Civil Rights Act of 1866, 42 U.S.C. §2000e, et seq., 42 U.S.C. §1981,
1983 and 1985, which prohibits violations of civil rights; the Equal Pay Act of
1963, 29 U.S.C. § 206(d)(1), which prohibits unequal pay based upon gender; the
Age Discrimination in Employment Act of 1967, as amended, and as further amended
by the Older Workers Benefit Protection Act, 29 U.S.C. § 621, et seq., which
prohibits age discrimination in employment; the Employee Retirement Income
Security Act of 1974, as amended, 29 U.S.C. §1001, et seq., which protects
certain employee benefits; the Americans with Disabilities Act of 1990, as
amended, 42 U.S.C. § 12101, et seq. and the Rehabilitation Act of 1973, which
prohibit discrimination against the disabled; the Family and Medical Leave Act
of 1993, as amended 29 U.S.C. § 2601, et seq., which provides medical and family
leave; the federal Worker Adjustment and Retraining Notification Act (as
amended) and similar laws in other jurisdictions; the Oklahoma
Anti-Discrimination Act, Okla. Stat., tit. 25, §§ 1101, et seq., the Fair Labor
Standards Act, 29 U.S.C. § 201, et seq., including the Wage and Hour Laws
relating to payment of wages, including, but not limited to, vacation pay,
commissions, and bonuses; and all other federal, state or local laws or
regulations prohibiting employment discrimination and/or governing the payment
of wages, benefits, and other forms of compensation, and any claims for wrongful
discharge, breach of contract, breach of the implied covenant of good faith and
fair dealing, fraud, discrimination, harassment, defamation, infliction of
emotional distress, termination in violation of public policy, retaliation,
including workers' compensation retaliation under state statutes, tort law;
contract law; wrongful discharge; discrimination; fraud; libel; slander;
defamation; harassment; emotional distress; breach of the implied covenant of
good faith and fair dealing; or claims for retaliation, or other claims arising
under any local, state or federal regulation, statute or common law. This
Release does not apply to the payment of any and all benefits and/or monies
earned, accrued, vested or otherwise owing, if any, to the Employee under the
terms of a Company sponsored tax qualified retirement or savings plan, except
that the Employee hereby releases and waives any claims that his termination was
to avoid payment of such benefits or payments, and that, as a result of his
termination, she is entitled to additional benefits or payments. Additionally,
this Release does not apply to any of Employee’s rights or obligations with
respect to indemnification or directors’ and officers’ liability coverage to
which Employee is entitled or subject in

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his capacity as a former officer or employee of the Company or SemGroup
Corporation. This Release does not apply to any claim or rights which might
arise out of the actions of the Company after the date the Employee signs this
Agreement. Further, notwithstanding anything herein to the contrary, nothing
herein or otherwise shall release the Company from any claims, rights or damages
that may not be released or waived as a matter of law.
5.    No Inducement. Employee agrees that no promise or inducement to enter into
this Agreement has been offered or made except as set forth in this Agreement,
that the Employee is entering into this Agreement without any threat or coercion
and without reliance or any statement or representation made on behalf of the
Company or by any person employed by or representing the Company, except for the
written provisions and promises contained in this Agreement.
6.    Protected Rights. Employee understands that nothing contained in this
Agreement limits Employee’s ability to file a charge or complaint with the U.S.
Equal Opportunity Commission, the National Labor Relations Board, the
Occupational Safety and Health Administration, the Securities and Exchange
Commission or any other federal, state, or local governmental agency or
commission (“Government Agencies”). Employee further understands that this
Agreement does not limit Employee’s ability to communicate with any Government
Agencies or otherwise participate in any investigation or proceeding that may be
conducted by any Government Agency, including providing documents or other
information, without notice to the Company. This Agreement does not limit
Employee’s right to receive an award for information provided to any Government
Agencies.
7.    Damages. The parties agree that damages incurred as a result of a breach
of this Agreement will be difficult to measure. It is, therefore, further agreed
that, in addition to any other remedies, equitable relief will be available in
the case of a breach of this Agreement.
8.    Advice of Counsel; Time to Consider; Revocation. Employee acknowledges the
following:
(a)    Employee has read this Agreement, and understands its legal and binding
effect. Employee is acting voluntarily and of Employee’s own free will in
executing this Agreement.
(b)    Employee has been advised to seek and has had the opportunity to seek
legal counsel in connection with this Agreement.
(c)    Employee was given at least 21 days to consider the terms of this
Agreement before signing it.
Employee understands that, if Employee signs this Agreement, Employee may revoke
it within seven days after signing it by delivering written notification of
intent to revoke within that seven day period. Employee understands that this
Agreement will not be effective until after the seven-day period has expired
(such date, the “Effective Date”).
9.    Severability. If all or any part of this Agreement is declared by any
court or governmental authority to be unlawful or invalid, such unlawfulness or
invalidity shall not invalidate any other portion of this Agreement. Any section
or a part of a section declared to be unlawful or invalid shall, if possible, be
construed in a manner which will give effect to the terms of the section to the
fullest extent possible while remaining lawful and valid.
10.    Amendment. This Agreement shall not be altered, amended, or modified
except by written instrument executed by the Company and the Employee. A waiver
of any portion of this Agreement shall not be deemed a waiver of any other
portion of this Agreement.

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11.    Counterparts. This Agreement may be executed in several counterparts,
each of which shall be deemed to be an original, but all of which together will
constitute one and the same instrument.
12.    Headings. The headings of this Agreement are not part of the provisions
hereof and shall not have any force or effect.
13.    Rules of Construction. Reference to a specific law shall include such
law, any valid regulation promulgated thereunder, and any comparable provision
of any future legislation amending, supplementing or superseding such section.
14.    Applicable Law. The provisions of this Agreement shall be interpreted and
construed in accordance with the laws of the State of Oklahoma without regard to
its choice of law principles.
IN WITNESS WHEREOF, the parties have executed this Agreement as of the dates
specified below.
/s/ Candice Cheeseman
Candice L. Cheeseman
Date:     August 2, 2017
SemManagement L.L.C., acting on behalf of itself and its Subsidiaries and
Affiliates
By: /s/ Kay Kittleman
Kay Kittleman

Title: Vice President Human Resources

Date: August 2, 2017
A C K N O W L E D G M E N T
I HEREBY ACKNOWLEDGE that SemManagement L.L.C. (the “Company”), in accordance
with the Age Discrimination in Employment Act of 1967, as amended by the Older
Workers Benefit Protection Act of 1990, informed me in writing that:
(1)    I should consult with an attorney before signing the Waiver and Release
Agreement ("Agreement") that was provided to me.
(2)    I may review the Agreement for a period of up to 21 days prior to signing
the Agreement. If I choose to take less than 21 days to review the Agreement, I
do so knowingly, willingly and on advice of counsel.
(3)    For a period of seven days following the signing of the Agreement, I may
revoke the Agreement, and that the Agreement will not become effective or
enforceable until the seven day revocation period has elapsed.

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(4)    The Company shall not accept my signed Agreement prior to the last day of
my employment.
I HEREBY FURTHER ACKNOWLEDGE receipt of this Agreement on the 2nd day of August,
2017.

WITNESS:
/s/ Mark D. Berman     /s/ Candice L. Cheeseman
Mark D. Berman                Candice L. Cheeseman