How to Update Existing Subscribers via CSV

How to use Bulk Upload to change subscriber details in bulk, why Subscriber IDs matter, and how to avoid creating duplicates.

Overview

When subscriber details change, such as a new phone number, updated email address, or corrected name, you can update many records at once using the Bulk Upload feature. The key is including each subscriber's existing Subscriber ID in the CSV. Reach matches the ID and overwrites the fields you provide, leaving everything else unchanged.

Subscriber ID is the key

Without the Subscriber_Id in your CSV, Reach treats each row as a new subscriber. This creates duplicates. Always confirm the IDs before running a bulk update.

What You'll Need

• Administrator access (Reach Admin or Department Admin).
• A list of the subscribers you want to update and their current Subscriber IDs.
• Their updated contact details or fields.
• A spreadsheet editor to build the CSV.

Step-by-Step: Updating Subscribers via CSV

Step 1: Get the Subscriber IDs

Before building your update file, you need the correct Subscriber ID for each person. There are two ways to get them:

• Search individually: Go to Subscribers, search for each person, and note their Subscriber ID from the leftmost column of the results table.
• Export from Analytics: Use the Analytics Messages view filtered by your department to export a list that includes Subscriber IDs alongside contact details.

Step 2: Build the update CSV

1. Download the official template from Subscribers Bulk Upload Get Bulk Upload Sample file here.
2. In the Subscriber_Id column, enter the existing ID for each subscriber you want to update.
3. Fill in the updated values in the relevant columns (e.g., a new email_address1 or corrected last_name).
4. For fields you are not changing, you can leave them blank. Reach will not overwrite existing values with blank cells.
5. Save the file as .csv format.

Step 3: Run the upload

1. Go to Subscribers Bulk Upload and upload your CSV.
2. In the Assign Criteria step, select the same Department the subscribers belong to.
3. Select the appropriate Category Groups, Categories, and Channels.
4. Review the summary and click Upload.

Step 4: Confirm the updates

1. Check Upload History for status. Pending means processing. Check back in a few minutes.
2. Once complete, search for one of the updated subscribers in the Subscribers tab to confirm the new values are showing.
3. If any rows failed, download the error CSV from Upload History and review the failed rows. See KB-017 for fixes.

What Gets Updated and What Does Not

Scenario	What happens
Subscriber_Id provided and field has a new value	That field is updated on the record.
Subscriber_Id provided and field is left blank in CSV	The existing value on the record is kept unchanged.
Subscriber_Id is blank	Reach creates a new subscriber record regardless of whether the name or contact details match an existing person.
Subscriber_Id does not match any existing record	That row fails with a 'Subscriber ID not found' error.
You change email_address1 to a new value	Future email notifications go to the new address only.

Tips for Success

Common Pitfalls

• ×Uploading updates without Subscriber IDs, creating duplicates instead of updating records.
• ×Overwriting phone numbers for subscribers who have replied STOP. The new number will not carry the opt-out.
• ×Running an update upload with the wrong department selected in Assign Criteria.
• ×Including subscribers from multiple departments in one update file.

Best Practices

• ✓Always double-check a small sample of Subscriber IDs against the portal before uploading a large update batch.
• ✓Keep a backup of the original subscriber data before running large updates.
• ✓After uploading, search for 2 or 3 updated subscribers to spot-check that the changes look right.
• ✓For updates that only affect contact details (no category change), assign the same categories as before in the Assign Criteria step.

Frequently Asked Questions

Q: Can I update a subscriber's department using bulk upload?

A: No. Department assignment cannot be changed through the upload. To move a subscriber to a different department, delete the record and re-add it in the new department.

Q: If I upload a subscriber with a new phone number, does it affect their STOP opt-out status?

A: Changing the phone number to a new one creates a new contact point. If the subscriber had replied STOP on the old number, that opt-out does not transfer to the new number.

Q: Can I deactivate subscribers through a bulk upload?

A: Reach does not currently have a status column in the standard bulk upload template. For bulk deactivation, contact Convey support.

Q: How do I know if my update actually changed anything?

A: After the upload completes, search for one of the updated subscribers in the Subscribers tab and check that the new values appear. You can also compare against your original export.

Q: Can I mix new subscribers and updates in the same file?

A: Yes. Rows with a Subscriber_Id are treated as updates. Rows with a blank Subscriber_Id are treated as new adds. Both work in the same upload.

Need More Help?

If you have followed the steps above and still require assistance, please refer to the relevant articles listed below for additional guidance.

• How Bulk Upload Works The full upload process.
• How to Fix Upload Errors What to do when update rows fail.