Originally Posted by
weero
Also - what I did twice before and it never occurs to the UA crew - BKK runs 24h and the UA service NRT-BKK often is really, really late. On both my severe delays ex LAX this year, I could connect to the BKK bird, spend about 4h in the lounge in BKK (including shower + food) and then hop on the very early connection to SIN on SQ or TG. That would save you the whole day and maybe you can cancel one hotel night in Singa.
IME, the LAX-NRT aircraft has usually been the one that goes on to BKK.
TG BKK lounges close at 1:00 AM and reopen at 5:15 AM, so not possible to overnight there. Some of the paid lounges may be open all night, but I'm not sure.
To the OP, I think it's nuts for UA to make you wait all day for UA's evening flight to SIN. You should insist that they book you some other carrier's day flight.