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.
Use our online converter which can be found here.
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.