is this behaviour is legal according to GPLv2 License statements ?
do I have the right to change the name of the modified open source ?
Could you please provide justification from licenses with the answer.
A name change is just a modification to the source code (etc) that embodies the name, and modification of "the work" is one of many things that is permitted by the GPL (subject the rest of the license terms).
Besides, a restriction on renaming would go against the Four Freedoms.
In a comment, you say "the name is different!".
Yes and no.
Yes. A name can be trademarked. But trademark law does not prevent you from using a non-trademarked name ... unless it that one is sufficiently similar as to cause confusion. Trademark is about stopping the use of a word / name, rather than forcing its use.
No. A name cannot be copyrighted independently. It is too small to be considered copyrightable. Besides, if you replace a name with a different name, you are not copying the original one.
No. To the extent that the name is part of the copyrighted work as a whole, the GPL says you can modify the work; see above.
Standard disclaimers apply. IANAL.
I recommend that you take the time to read the GNU license itself, and the accompanying FAQs. The latter have been professionally translated into many languages ... probably including yours.