Hi Jess,
Registrant Checklist Alert columns aren't currently customizable. You can configure the alert's recipients, schedule, session/event scope, access password, and whether recipients can mark participants, but not add, remove, or replace checklist fields such as work phone with mobile phone. I would recommend submitting this as feedback for our product team to review within Product Ideas
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Julia Plymack
Senior Customer Success Manager
Cvent
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