The XES standard is used for process mining.
The DCR XML Log format is a log format dedicated for declarative process mining.
The main difference between XES and DCR XML Log is that XES is more verbose.
DCR Solutions provide a XSLT that can convert DCR XML Log into XES. It can be downloaded from this link.
Variout tools exists that can convert xml using a XSLT. An example is the the Free Online XSLT Transformer.