How do I migrate docs after a schema change?

const payload = require('payload');

require('dotenv').config();

payload.init({
  secret: process.env.PAYLOAD_SECRET,
  mongoURL: process.env.MONGO_URL,
  local: true,
});

const resaveCollection = async () => {
  const args = process.argv.slice(2); // nodejs command line args are an array that begin at the third item
  const [
    collectionSlug,
    overrides
  ] = args || [];

  const results = await payload.find({
    collection: collectionSlug,
    depth: 0,
    limit: 700,
  });

  try {
    await Promise.all(results.docs.map(async (result) => {
      const { id } = result;

      if (collectionSlug) {
        try {
          await payload.update({
            collection: collectionSlug,
            id,
            data: {
              ...overrides || {}
            },
          })

          console.log(`Document in '${collectionSlug}' with id '${id}' updated successfully`);
        } catch (e) {
          payload.logger.error(`Document in '${collectionSlug}' with id '${id}' failed to update`);
          payload.logger.error(e);
        }
      } else {
        console.log(`No document found in '${collectionSlug}' with id '${id}'`);
      }
    }));
  } catch (e) {
    payload.logger.error('Something went wrong.');
    payload.logger.error(e);
  }

  console.log('Complete');
  process.exit(0);
};

resaveCollection();