Modify string

What it does

This action transforms, extracts, or stores data used by later workflow steps. The converted flow must preserve the source expression, output variable, and any formatting or type conversion behavior.

How Flow Migrator maps it

Flow Migrator maps this to Compose expression + Set variable using Data Operations / Variables. Performs supported trim, zero-based start/end/index extraction, literal replacement, length and case-neutral find operations with typed assignments and bounds guards. Unknown operations and ambiguous comparison settings stop instead of producing a no-op. Flow Migrator has a direct or proven best-effort conversion path for this mapping.

Common migration issues

• Validate expression syntax, data types, escaping, HTML output, and array/object handling in Power Automate.
• Run a test instance and compare outputs against the original Nintex workflow before production migration.

Validation checklist

1. Open the generated flow and confirm the action card imported correctly.
2. Validate connection references and required settings before running the flow.
3. Test with representative source data from the original workflow.