Hello Keithtanjf37
We do have an English-speaking SBB Community: Questions and answers - SBB CFF FFS Community
If you bought your tickets from SBB, you can only exchange them by calling the SBB Contact Center staff (+41 51 225 78 56, 24/7, waiting times may happen) or at any SBB Travel Center. If you obtained your tickets from a different railway company or a reseller such as Trainline, kindly refer to the relevant provider.
Kindly yours,
Roland