Concerning a new on-line petition to replace UNRWA:
UNRWA reports to the UN General Assembly, which will not allow UNHCR  or any other UN agency  to replace UNRWA.  
The UN will simply not allow one UN agency to replace another UN agency.
However, the UN cannot stop a effective campaign against UNRWA policies. 
Please review
Have worked against the UNRWA policies for 37 years. 
There is no reason to invest in strategy doomed to failure.