Exhibit 10.50



FS Investment Corporation II

201 Rouse
Boulevard

Philadelphia,
PA 19112



| | March 16, 2018
| | --------------



ING Capital LLC, as Administrative Agent

1133 Avenue of the Americas

New York, NY 10036



and the Lenders (as defined below)



| | Re: | FS Investment Corporation II – Consent and Modification in relation to Transition Events
| | --- | ----------------------------------------------------------------------------------------



Ladies and Gentlemen,



Reference is hereby made to the Senior Secured
Revolving Credit Agreement, dated as of February 23, 2016 (as amended by that certain Amendment No. 1 to Senior Secured Revolving
Credit Agreement, dated as of April 25, 2016, and as further amended, restated, supplemented or otherwise modified from time to
time, the “Credit Agreement”; capitalized terms not otherwise defined herein shall have the meanings ascribed
to them in the Credit Agreement), among FS INVESTMENT CORPORATION II, a Maryland corporation (“us” or “we”),
the several banks and other financial institutions or entities from time to time party to the Credit Agreement as lenders (the
“Lenders”), and ING CAPITAL LLC, as administrative agent for the Lenders under the Credit Agreement (in such
capacity, together with its successors in such capacity, the “Administrative Agent”).



FSIC II Advisor, LLC (“FSIC II Advisor”)
currently provides investment advisory and administrative services to us pursuant to the Investment Advisory and Administrative
Services Agreement, dated as of February 8, 2012, by and between us and FSIC II Advisor (the “Current Investment Advisory
Agreement”). GSO / Blackstone Debt Funds Management LLC (“GDFM”) currently serves as our investment
sub-advisor pursuant to the Investment Sub-Advisory Agreement, dated as of February 8, 2012, by and between GDFM and FSIC II Advisor
(the “Current Investment Sub-Advisory Agreement”).



On (i) December 11, 2017, we filed a current report
with the U.S. Securities and Exchange Commission on Form 8-K (a copy of which is attached hereto as Exhibit A, the “Filing”)
and (ii) January 18, 2018, we filed a definitive proxy report statement with the U.S. Securities and Exchange Commission on Schedule
14A (a copy of which is attached hereto as Exhibit B, the “Proxy”) announcing, among other things (collectively,
the “Proposed Transition”), (a) GDFM’s intended resignation as our investment sub-advisor and termination
of the Current Investment Sub-Advisory Agreement in April 2018 and (b) a proposed transition of our investment advisory services
to a new joint venture relationship between affiliates of Franklin Square Holdings, L.P. (“FS Investments”)
and KKR Credit Advisors (US) LLC (“KKR”), which is proposed to ultimately take the form of a newly formed entity
jointly operated by one or more affiliates of FS Investments and KKR (such proposed new joint investment advisor entity, the “Joint
Advisor”).













In furtherance of the Proposed Transition, we,
FSIC II Advisor, KKR and the Joint Advisor have taken or intend to take one or more of the following actions, each as more fully
described in the Filing and the Proxy and subject to the terms and conditions set forth in the applicable definitive documents
(collectively and together with all other transactions reasonably necessary to achieve the Proposed Transition, the “Transition
Events”):



| | (a) | the renewal of the Current Investment Advisory Agreement for an additional one-year term commencing on December 10, 2017;
| | --- | -------------------------------------------------------------------------------------------------------------------------



| | (b) | the entry into that certain Engagement Letter, dated as of December 13, 2017, by and among FSIC II Advisor, other affiliated
investment advisors, KKR and KKR’s broker-dealer affiliate (the “Sourcing and Administrative Services Agreement”);
| | --- | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | (c) | the entry into an interim investment advisory agreement that meets the applicable requirements of Rule 15a-4 under the Investment
Company Act by and between us and KKR, substantially in the form of that certain Interim Investment Advisory Agreement by and between
us and KKR delivered to the Administrative Agent by us on March 9, 2018 (the “Interim Advisory Agreement”);
| | --- | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | (d) | the termination of the Current Investment Sub-Advisory Agreement;
| | --- | -----------------------------------------------------------------



| | (e) | the entry into investment advisory and/or administration agreements by and between us and one or each of FSIC II Advisor and/or
KKR, substantially in the form of (i) that certain Investment Advisory Agreement between us and FSIC II Advisor, attached as Exhibit
A to the Proxy and (ii) that certain Investment Advisory Agreement between us and KKR, attached as Exhibit B to the
Proxy (together, the “Co-Advisory Agreements”);
| | --- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | (f) | the entry into investment advisory and/or administration agreements by and between us and the Joint Advisor, substantially
in the form of that certain Investment Advisory Agreement between us and FS/KKR Advisor, LLC, attached as Exhibit Cto the
Proxy (the “Joint Advisor Advisory Agreement”);
| | --- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | (g) | the resignation of GDFM as our investment sub-advisor;
| | --- | ------------------------------------------------------



| | (h) | the provision by KKR and/or KKR’s broker-dealer affiliate of certain origination, administrative and other services to
FSIC II Advisor;
| | --- | ---------------------------------------------------------------------------------------------------------------------------------------



| | (i) | FSIC II Advisor and KKR serving as our co-investment advisors (“Co-Advisory Status”);
| | --- | -------------------------------------------------------------------------------------



| | (j) | the Joint Advisor serving as our investment advisor (“Joint Advisory Status”);
| | --- | ------------------------------------------------------------------------------





2







| | (k) | upon or after the effectiveness of Joint Advisory Status, the resignation of FSIC II Advisor as our investment advisor or the
resignation of FSIC II Advisor and/or KKR as our co-investment advisors, as applicable;
| | --- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | (l) | changes to the size and composition of our board of directors; and/or
| | --- | ---------------------------------------------------------------------



| | (m) | the receipt by one or more of FSIC II Advisor, KKR and/or the Joint Advisor of management and/or incentive fees from us in
connection with or arising from any of the foregoing.
| | --- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



One or more of the Transition Events may require
your consent under the Credit Agreement and the other Loan Documents. Accordingly, we hereby request your consent under the Credit
Agreement and the other Loan Documents to the undertaking of one or more of the Transition Events, and the Lenders signatory hereto
and the Administrative Agent hereby so consent on the terms and subject to the conditions contained in this consent and modification
letter.



Effective as of the date hereof, and subject
to the terms and conditions set forth herein, you hereby consent to the following (items (1) through (4) collectively, the “Consent”):



1.           The resignation of GDFM as our sub-advisor and the termination of the Current Investment
Sub-Advisory Agreement; provided that,



a.           the
definition of “Affiliate Agreement” in Section 1.01 of the Credit Agreement shall be amended by deleting clause (ii)
thereof;



b.           the
definition of “Sub-Advisor” in Section 1.01 of the Credit Agreement shall be amended by deleting such definition in
its entirety; and



c.           clause
(n) of Article VII shall be amended by deleting subclause (ii) in its entirety.



2.           The
entry into one or more of the Sourcing and Administrative Services Agreement, the Interim Advisory Agreement, the Co-Advisory Agreements
and/or the Joint Advisor Advisory Agreement; provided that any of the Interim Advisory Agreement, the Co-Advisory Agreements
or the Joint Advisory Agreement, once entered into, shall be deemed an “Affiliate Agreement” for all purposes under
the Credit Agreement; provided that, for the purposes of Section 6.11(b) of the Credit Agreement, we may freely terminate
one or both of the Interim Advisory Agreement and/or the Co-Advisory Agreements to the extent such termination is in connection
with the effectiveness of Co-Advisory Status or Joint Advisory Status, as applicable.



3.           The entry into the Co-Advisory Status pursuant to the Co-Advisory Agreements; provided that, upon entry into any such status,



a.           the
definition of “Investment Advisor” in Section 1.01 of the Credit Agreement shall be deemed to be: “(x) FSIC II
Advisor, LLC, a Delaware limited liability company, or an Affiliate thereof, in each case so long as it is a Controlled Affiliate
of Franklin Square Holdings, L.P. and (y) KKR Credit Advisors (US) LLC or an Affiliate thereof, in each case so long as it is a
Controlled Affiliate of KKR & Co. LP, as co-advisors”;





3







b.           each
reference to “Affiliate” in Sections 3.17 and 5.02(b) of the Credit Agreement shall be deemed to be a reference to
“Affiliate (other than KKR or any of its Affiliates (except the Investment Advisor) to the extent such entity satisfies the
definition of “Affiliate” solely as a result of the entry into the Co-Advisory Status)”;



c.           the
reference to “FSIC II Advisor, LLC (so long as it is an Affiliate of Franklin Square Holdings, L.P.)” in clause (n)
of Article VII of the Credit Agreement shall be deemed to be a reference to “both FSIC II Advisor, LLC or one of its Affiliates
(in each case, so long as it is a Controlled Affiliate of Franklin Square Holdings, L.P.) and KKR Credit Advisors (US) LLC or one
of its Affiliates (in each case, so long as it is a Controlled Affiliate of KKR & Co. LP)”; and



d.           the
definition of “Information” in Section 9.13 of the Credit Agreement shall be deemed to also include information received
from the Investment Advisor relating to the Investment Advisor, the Borrower, any of its Subsidiaries, any of their respective
businesses or any Portfolio Investment (including its Value), other than any such information that is available to the Administrative
Agent, the Issuing Bank or any Lender on a nonconfidential basis prior to the disclosure by the Investment Advisor.



4.          The
entry into the Joint Advisory Status pursuant to the Joint Advisor Advisory Agreement and, upon or after entry into any such status,
the resignation of FSIC II Advisor as our investment advisor or the resignation of FSIC II Advisor and/or KKR as our co-investment
advisors, as applicable; provided that, upon entry into any such status,



a.           the
definition of “Investment Advisor” in Section 1.01 of the Credit Agreement shall be deemed to be “FS/KKR Advisor,
LLC (so long as it is jointly managed by (i) Franklin Square Holdings, L.P. and/or one or more of its Controlled Affiliates and
(ii) KKR & Co. LP and/or one or more of its Controlled Affiliates)”;



b.           each
reference to “Affiliate” in Sections 3.17 and 5.02(b) of the Credit Agreement shall be deemed to be a reference to
“Affiliate (other than KKR or any of its Affiliates (except the Investment Advisor) to the extent such entity satisfies the
definition of “Affiliate” solely as a result of the entry into the Co-Advisory Status and/or the Joint Advisory Status)”;



c.           the
reference to “FSIC II Advisor, LLC (so long as it is an Affiliate of Franklin Square Holdings, L.P.)” in clause (n)
of Article VII of the Credit Agreement shall be deemed to be a reference to “FS/KKR Advisor, LLC (so long as it is jointly
managed by (i) Franklin Square Holdings, L.P. and/or one or more of its Controlled Affiliates and (ii) KKR & Co. LP and/or
one or more of its Controlled Affiliates)”; and



d.           the
definition of “Information” in Section 9.13 of the Credit Agreement shall be deemed to also include information received
from the Investment Advisor relating to the Investment Advisor, the Borrower, any of its Subsidiaries, any of their respective
businesses or any Portfolio Investment (including its Value), other than any such information that is available to the Administrative
Agent, the Issuing Bank or any Lender on a nonconfidential basis prior to the disclosure by the Investment Advisor.





4







The Consent will remain effective (i) during the
eighteen (18) month period following the date hereof, so long as one of either the Sourcing and Administrative Services Agreement
or the Interim Advisory Agreement is in full force and effect at such time or (ii) at any time, if one of either the Co-Advisory
Status or Joint Advisory Status has become effective.



Additionally, you and we hereby agree, upon the
effectiveness of Co-Advisory Status or Joint Advisory Status (or earlier upon the request of the Administrative Agent or us), to
take such actions (including entering into mutually agreeable amendments, supplements or other modifications to the Loan Documents)
that are reasonably requested by the Administrative Agent or us to document the advisory relationship and the other matters contemplated
in this consent and modification letter and to otherwise effectuate the purposes and objectives of this consent and modification
letter, in each case, on a going-forward basis.



To induce the other parties hereto to enter into
this consent and modification letter, the Borrower represents and warrants to the Administrative Agent and each Lender that, as
of the date hereof and after giving effect to this consent and modification letter, (i) the representations and warranties set
forth in Article 3 of the Credit Agreement and each other Loan Document are true and correct in all material respects (other than
any representation or warranty already qualified by materiality or Material Adverse Effect, which shall be true and correct in
all respects) on and as of the date hereof or, as to any such representations and warranties that refer to a specific date, as
of such specific date, with the same effect as though made on the date hereof and (ii) no Default or Event of Default has occurred
or is continuing.



Except as expressly modified hereby, all of the
representations, warranties, terms, covenants, conditions and other provisions of the Credit Agreement and the other Loan Documents
and the Liens granted thereunder shall remain unchanged and shall continue to be, and shall remain, in full force and effect in
accordance with their respective terms.  The consents and modifications set forth herein shall be limited precisely as provided
for herein and shall not be deemed to be an amendment to, waiver of, consent to or modification of any other terms or provisions
of the Credit Agreement or any other Loan Document or of any transaction or further or future action on the part of the Borrower.
Upon and after the execution of this consent and modification letter by each of the parties hereto, each reference in the Credit
Agreement to “this Agreement”, “hereunder”, “hereof” or words of like import referring to the
Credit Agreement, and each reference in the other Loan Documents to “the Credit Agreement”, “thereunder”,
“thereof” or words of like import referring to the Credit Agreement, shall mean and be a reference to the Credit Agreement
as modified hereby.



The contemporaneous exchange and release of executed
signature pages by each of the Persons contemplated to be a party hereto shall render this consent and modification letter effective.
This consent and modification letter may not be amended or any provision hereof or thereof waived or modified except by an instrument
in writing signed by each of the parties hereto. This consent and modification letter may be executed in counterparts (and by different
parties hereto on different counterparts), each of which shall constitute an original, but all of which when taken together shall
constitute a single contract. This consent and modification letter constitutes the entire contract between and among the parties
relating to the subject matter hereof and supersedes any and all previous agreements and understandings, oral or written, relating
to the subject matter hereof. Delivery of an executed counterpart of this consent and modification letter by telecopy or electronic
mail shall be effective as delivery of a manually executed counterpart of this consent and modification letter.





5







THIS CONSENT AND MODIFICATION LETTER SHALL
BE CONSTRUED IN ACCORDANCE WITH AND GOVERNED BY THE LAW OF THE STATE OF NEW YORK.



EACH PARTY HERETO HEREBY WAIVES, TO THE FULLEST
EXTENT PERMITTED BY APPLICABLE LAW, ANY RIGHT IT MAY HAVE TO A TRIAL BY JURY IN ANY LEGAL PROCEEDING DIRECTLY OR INDIRECTLY ARISING
OUT OF OR RELATING TO THIS CONSENT AND MODIFICATION LETTER OR THE TRANSACTIONS CONTEMPLATED HEREBY (WHETHER BASED ON CONTRACT,
TORT OR ANY OTHER THEORY). EACH PARTY HERETO (A) CERTIFIES THAT NO REPRESENTATIVE, AGENT OR ATTORNEY OF ANY OTHER PARTY HAS
REPRESENTED, EXPRESSLY OR OTHERWISE, THAT SUCH OTHER PARTY WOULD NOT, IN THE EVENT OF LITIGATION, SEEK TO ENFORCE THE FOREGOING
WAIVER AND (B) ACKNOWLEDGES THAT IT AND THE OTHER PARTIES HERETO HAVE BEEN INDUCED TO ENTER INTO THIS CONSENT AND MODIFICATION
LETTER BY, AMONG OTHER THINGS, THE MUTUAL WAIVERS AND CERTIFICATIONS IN THIS SECTION.



The provisions of Sections 9.01, 9.07, 9.09
and 9.12 of the Credit Agreement are hereby incorporated by reference mutatis mutandis as if fully set forth herein.



[Signature pages follow]



6







If you are in agreement with the foregoing, please
sign and return the enclosed counterpart of this consent and modification letter.



| | FS INVESTMENT CORPORATION II, as Borrower
| | -----------------------------------------
| |                                          
| | By:                                      
| | Name:                                    
| | Title:                                   



[Consent and Modification Letter]













| | ING CAPITAL LLC, as Administrative Agent
| | ----------------------------------------
| |                                         
| | By:                                     
| | Name:                                   
| | Title:                                  
| |                                         
| | By:                                     
| | Name:                                   
| | Title:                                  



[Consent and Modification Letter]













| | BARCLAYS BANK PLC, as a Lender
| | ------------------------------
| |                               
| | By:                           
| | Name:                         
| | Title:                        



[Consent and Modification Letter]













| | CITIBANK, N.A., as a Lender
| | ---------------------------
| |                            
| | By:                        
| | Name:                      
| | Title:                     



[Consent and Modification Letter]













| | CREDIT SUISSE AG, CAYMAN ISLANDS
        BRANCH, as a Lender
| | ------------------------------------------------------------
| |                                                             
| | By:                                                         
| | Name:                                                       
| | Title:                                                      
| |                                                             
| | By:                                                         
| | Name:                                                       
| | Title:                                                      



[Consent and Modification Letter]













| | DEUTSCHE BANK AG, NEW YORK BRANCH,
        as a Lender
| | ------------------------------------------------------
| |                                                       
| | By:                                                   
| | Name:                                                 
| | Title:                                                
| |                                                       
| | By:                                                   
| | Name:                                                 
| | Title:                                                



[Consent and Modification Letter]











Exhibit
A



[See
Attached]













Exhibit
B



[See
Attached]