If the hotel's solution is that you can walk (which probably won't be pleasant in Shanghai summer weather) to use the pool at LRM, ask them to change your reservation to LRM for the same price.

BTW, the LRM pool is indoors in a sort of atrium on about the sixth floor. It's a very long lap pool with space (width) for two or three lanes and IMO a more attractive setting than the indoor pool at the Hongta (former StR). IIRC it's turquoise tile and reasonably heated but certainly not bathtub temperature. However, neither would be in contention for my favorite Starwood indoor pools list.