Hi @YannickM
Yes you can rewrite the java code and recompile the java file to class and rewrite the OOTB one.
file location> Windchill\src\com\ptc\windchill\enterprise\change2\change2ClientResource.java
rbEntry
@RBEntry("<br><b>CONFIRMATION</b>: Submit the change object now?<br><br>Click \"Submit Now\" to submit the change object now.<br>Click \"Submit Later\" to submit the change object at another time.")
@RBComment("The string displayed to a user when they attempt to submit a change object where Submit Now is enabled. The <br> and <b> tags are needed because this text is dumped directly into HTML content at runtime. There are three distinct sentences. the first is the header message. The remaining two are the instructions.")
public static final String SUBMIT_NOW_MESSAGE = "SUBMIT_NOW_MESSAGE";
just change the RBEntry to different text and compile the file.
Following article describes how to compile java in windchill CS361074 - How to compile custom Java class in Windchill PLM
PetrH