I did an online checkin yesterday and today went back into my checkin to change seats. I came up to the Check In Summary screen which displays the following message.

"The following seats have been allocated for your flight. You may change your seats now if you wish"

However, there is no button (or option) to the seat map to select and change alloted seats.

I am assuming that this is a bug (based on the msg that appears on the screen) or has SIA stopped allowing seat changes after an online checkin has taken place ?