Practice moved from 4:00 to 5:15, starting the 12th. You found out from the coach's email at lunch. The other parent still thinks pickup is at the old time. If you drop that into the thread that already has last weekend in it, the time change will disappear under the weekend.
Send a short, dated notice with one ask. Nothing else.
Neutral is a discipline, not a tone of voice
Write the change as a cold reader would need it:
- What was true: Tuesday pickup at 4:00 at the school lot.
- What is true on the 12th: practice ends 5:15; pickup at the field entrance, not the lot.
- What you need: confirm they can take the 5:15, or you will keep Tuesdays through the month.
That is the whole message. "As usual you weren't on the email" is not a reason. "Coach sent this today" is.
Urgency is a claim. If the first changed Tuesday is three weeks away, the honest deadline is "by the weekend" — not "ASAP." Save the real clock for the day the coach moves practice to tomorrow.
A briefing keeps the ask visible. Your assistant can pull the coach's sentences out of the session. You delete the commentary before you approve.
Your word for them does not travel
You may have renamed them on your contacts list to something they have never been called. That nickname is private. It is how you address them to your assistant. It is not how the package addresses them.
If the draft opens with that word, rewrite it. The server will refuse a send that puts a private nickname into text they would read, unless you have chosen to share that one word. Sharing is a checkbox you set on purpose. A rename resets it.
Use the name they publish. Use their address. Do not let a pet name become the first line of a custody-adjacent email.
One ask, then stop
Write it so they can answer from a phone. Confirm, swap, or you cover Tuesdays. A sufficient reply is one line. If they want to talk about the season, that is a different message on a different day.
They do not need an account. Email and the link are enough. If they already have a RelayLink account, you need an accepted contact. You review the draft; you send it. Block, if it ever comes to that, is silent — they will not get a notice that you ended the channel.
A reply is how you know they have it. A fetched link is not a read. You cannot see whether they put the 12th on their calendar. After they answer, the thread holds the change. The next coach email can land in a session and become another short notice, if you connect your assistant, instead of another weekend argument with a time buried in it.