Hello vIruch67,
Consider you have a dataset similar to this and you only want to update the location ID of New York and Santa Clara.

Step 1: Use a find + Replace on location ID and replace the blanks with the ID you want to fill it with (In this case 1)

Step 2: Hit on the filters on the top right corner of the Find + Replace panel.

Step 3: Pull a filtergram on City and select Santa Clara and New York

Step 4: Hit save on the steps panel and you will get your desired view.

I hope this helps!
Thank You and Best Regards,
Akshay