XSLT mapping to replcae ns1 from output xml payload

Hi,

My main graphical mapping is returning payload as below and same is been passed to third party but we need to replace "ns1" string from output payload to 'pidx".

Could you please provide me the XSLT code to achive the same or is there any better approach to do it.

Graphical output payload:

Required Output:

Thanks & Regards,

Nid Fatima