Slack Zoho Desk integration

Slack Zoho Desk integration

Hi,

I've created a flow which creates a new ticket in Zoho Desk if someone sends a message within a specific Slack channel. I want to include the user's name in the subject line. However, the variable UserId only includes a id like UAE194403. How can I adjust this userid to someones name? Maybe a custom function which determines IF userid = UAE194403, then user name is TEST. Then I can add this name variable to the subject line