A return message is easier to write when you state the item's condition plainly and offer a specific time to drop it off. If there is minor wear or damage, mention it up front.
By pingpong ·
A text to start with
I borrowed [item] from [name] about [time ago]. I'd like to return it on [date or range]. The item is in [good condition / has minor wear / has a small issue I should mention]. I want to thank them sincerely without overdoing it, and suggest a time to hand it back. Please draft a short text message. I'll send it from my own phone.
Example request. Change the details to fit your situation.
What to check in the answer
Check that anything the draft says about the item's condition is accurate. If there is damage or wear you haven't mentioned, add it yourself, since the person would rather hear it beforehand than find it at the handoff. Make sure the times offered fit your real schedule. If you gave no reason for the delay, delete any explanation the draft made up, because an invented excuse can hurt more than saying nothing.
What to do next
Send the message when you know your schedule is clear. If the person proposes another time, reply to confirm the one that works. Once you've agreed on a handoff, put it in your calendar so it happens.