In principle yes, but in practice there are T&Cs and some restrictions:

https://www.qatarairways.com/en/Priv...onditions.html

https://www.qatarairways.com/en/Priv...onditions.html

There will also need to be availability for a new reward booking between your origin and destination on the new date you wish to travel. You can't just change one sector without that availability on the whole journey, or change to any flights on any date (unless one or more of your flights is cancelled or significantly retimed, then greater flexibility is possible).