Is this Data object referring to Internal or External Data Source??
from my understanding to your question.
1)you can take export of first Data Object say X using i command
icommand -cmd export -name "/your DO" -file "D:\temp\X.xml"
2) you can open this exported data object xml file and replace all the occurrence of
X with the second data object Y along with the folder name
3)delete the second data object Y in the server(along with folder)
4)now import this DO to server
icommand -cmd import -file "D:\temp\X.xml"
now your Data object Y will be replaced with data object X along with its contents
note** take a back up of both objects while doing so....