FIRST AMENDMENT TO LEASE

Exhibit 10.13

FIRST AMENDMENT TO LEASE

THIS FIRST AMENDMENT TO LEASE (“Amendment”) is dated as of August 28, 2011, between 1400 Fashion Island LLC, a Delaware limited liability company (“Landlord”), and RING CENTRAL, INC., a California corporation (“Tenant”).

RECITALS

A. Landlord and Tenant entered into that certain Office Lease dated as of April 1, 2011 (the “Lease”), pursuant to which Tenant leases from Landlord certain premises on the 7th floor known as Suite 700 and containing 18,102 rentable square feet (the “Existing Premises”) of the building (the “Building”) known as Century Centre II, located at 1400 Fashion Island Blvd., San Mateo, California, which Existing Premises is more thoroughly described in the Lease. Capitalized terms not otherwise defined herein shall have the meanings given them in the Lease.

B. Landlord and Tenant presently desire to amend the Lease in order to add to the Lease additional premises known as Suite 602 on the 6th floor of the Building, and modify the Lease in certain other respects, all on the terms and conditions set forth herein.

NOW, THEREFORE, in consideration of the foregoing, the parties hereto agree as follows:

1. Amendment of Lease With Respect to Approval Process for the Existing Premises

The parties hereto acknowledge and agree that they have reached agreement on Floor Plan SP-12 for the Existing Premises prepared by RMW architecture & interiors (“Approved Floor Plan”), which was approved by Tenant’s General Counsel, John Marlow, on behalf of Tenant in his letter to 1400 Fashion Island LLC dated August 17, 2011 and which is attached hereto as Exhibit “C.” Upon execution and delivery of this First Amendment to Lease by both Landlord and Tenant, Landlord shall submit the Approved Floor Plan to the City of San Mateo for permit approval (the “Permit Application”). Because of the extended period of negotiations between the parties with respect to the Approved Floor Plan, and in order to expedite the commencement of construction by Landlord of the Tenant Improvements to the Existing Premises, Section 3 of Exhibit “B” attached to the Lease, which section is entitled “ Preparation of Plans and Construction Schedule and Procedures,” is hereby amended so that the Tenant approvals provided for therein, including but not limited to the Tenant approvals described in (i) Section 3(b) with respect to Working Drawings, (ii) Section 3(d) with respect to Engineering Drawings, and (iii) Section 3(f) with respect to the Plans, shall no longer be required by Landlord, and Tenant

hereby waives its right to give such approvals, so that upon receipt of the City’s approval of the Permit Application and the issuance by the City of an appropriate permit for construction of the Tenant Improvements, Landlord shall be authorized, without need for any further consent or approval from Tenant, to proceed with the commencement of construction of the Tenant Improvements to the Existing Premises.

2. Additional Premises.

Tenant acknowledges that the Additional Premises contain certain furniture (the “Existing Furniture”) which is listed on Exhibit “B” attached hereto. Tenant further acknowledges and agrees that the Existing Furniture is currently Landlord’s property. On or before September 15, 2011, Tenant may request that Landlord, at Landlord’s sole cost and expense, remove or (if necessary) disassemble all or some portion of the Existing Furniture. Except for such furniture that Landlord removes at Tenant’s request as above stated, on and after September 15, 2011, in consideration of the promises contained in this First Amendment, all right, title and interest in the Existing Furniture remaining in the Premises shall be deemed transferred to Tenant by Landlord, and Landlord shall retain no further right, title or interest in same. Landlord makes no representation concerning, nor does Landlord warrant, the condition of the Existing Furniture nor shall Landlord be responsible for servicing or maintaining the Existing Furniture. Landlord shall have no liability to Tenant, nor shall Tenant be entitled to any reduction in rent or any offset whatsoever, should any of the Existing Furniture fail to operate or otherwise fail to properly function.

3. Monthly Rent and Operating Expenses.

Simultaneously with Tenant’s delivery to Landlord of an executed copy of this First Amendment, and in addition to the Additional Premises Security Deposit provided by Section 4 of this First Amendment, Tenant shall pay to Landlord an amount equal to the Monthly Rent for the Additional Premises payable for the first full month after the occurrence of the Effective Date for which rent is due (i.e., rent for 12/1/11 to 12/31/11 equal to $24,309.60), which amount shall be applied to the first full month of Monthly Rent due and payable, after the application of the three-month rent concession granted to Tenant, with respect to the Additional Premises.

Tenant hereby warrants, convenants and agrees that as of the Effective Date Tenant shall no longer have any claim or right whatsoever in or to Suite 500, including Right of First Offer, all claim or right to which is hereby relinquished by Tenant.

“D. Landlord’s Denial and Tenant’s Conditional Right to Terminate. In the event that Tenant receives the Expansion Denial Letter or no response from Landlord within the Landlord Response Period, then Tenant shall have a onetime right to early terminate the lease (“Early Termination Right”) without penalty upon payment by cashier’s or certified check to Landlord of an amount equal to

$587,342.96 (the “Termination Payment”) calculated as follows: (i) eight (8) times the Monthly Rent for the Premises (i.e. Suite 700) based on the rent for the fortieth (40th) full calendar month of the Term of the Lease (i.e. 8 x $46,879.89 = $375,039.12), plus (ii) eight (8) times the Monthly Rent for the Additional Premises (i.e. Suite 602) based on said rent for the fortieth (40th) full month of the Term for the Additional Premises (i.e. 8 x $26,537.98 = $212,303.84). Tenant may exercise the Early Termination Right no later than thirty (30) business days after the termination of the Landlord Response Period by sending Landlord a formal written notice (“Termination Letter”) exercising such Early Termination Right together with (i) the Termination Payment, and (ii) an executed Letter of Intent for a minimum 40,000 rentable square feet at a new location, which Letter of Intent Landlord agrees to hold in the strictest confidence. Within sixty (60) days after Landlord’s receipt of Tenant’s Termination Letter, Tenant shall also deliver to Landlord a fully executed lease for a minimum 40,000 rentable square feet at said new location, which lease Landlord agrees to hold in the strictest confidence. Provided that Tenant has complied with all of the above requirements, Termination shall be effective at the end of the thirty ninth (39th) month of the Lease Term. Landlord shall have the right to market the Premises upon receipt of the Termination Letter and Termination Payment.”

IN WITNESS WHEREOF, the parties have executed this Amendment as of the date and year first above written.

Certificate of Tenant

I, John Marlow, Secretary of Tenant, hereby certify that the officers executing the foregoing First Amendment To Lease on behalf of Tenant is/are duly authorized to act on behalf of and bind the Tenant.

EXHIBIT A

EXHIBIT B

FF&E - 1400 Fashion Island Boulevard, Suite 602

EXHIBIT “C”