> ## Documentation Index
> Fetch the complete documentation index at: https://docs.slm.m1amdocs.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Enable Existing Customer to Purchase a Single-Event Product

You can enable existing customers to purchase a single-event product using their on-file payment method. To support this functionality, you must use the Subscribe APIs.

* \*\*Use Case Number:\*\*2-4-14
* \*\*Completed By:\*\*Software Developer
* **Estimated Completion Time:**\<3 days

## Pre-Condition

Customer exists in the system.

Customer already has a valid method of payment on file.

## Post-Condition

One-time transaction is generated if applicable, including tax if applicable, and charge to customer's on-file payment information.

Account has been granted appropriate entitlements

**Parent topic:**[Single Event Products](../topics/r_singleEventProducts)


This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.