Hi,

Thank you very much for your question!

I'm afraid now you have to change the tag one task by one task.
Could you please tell us your scenario of this operation, that is, when you need to change a tag of so many tasks at a time, so that we may add it into our need list to develop later？

Look forward to your reply.
Happy New Year!

And, will you also need to change the tags of the already completed tasks?