Hello,
I am asking for assistance from the community of great genealogy mavens. Is there any way to find out the original European surname after someone has made aliyah and changed their surname into something more Israeli. Relatives tried a few times to find out by contacting an individual with this new surname in Israel, but he never replied. We have letters from years ago with this story, but no conclusive proof. It would solve a question I have carried around for several decades. The family emigrated from Poland circa 1900.

best regards,
Joanne Grosman
researching Grosman, Bocian, Kremsdorf

The Population and Immigration Authority (part of the Ministry of Interior Affairs) provides a service to locate any resident of Israel. 
It is inexpensive (15 NIS) and they can try and locate a person based on previous names as well. Of course, the more information you provide, the more likely it is that they succeed. 
However, you have to reside in Israel in order to file a request.
Here's a link: https://www.gov.il/en/service/address_identification

I have a relative who made aliyah from Ukraine in the early 1900s.  I found his formal name change in a published listing from 1947 pre-state in the IGRA database https://genealogy.org.il/AID/
this is the source documentation from that record
This record comes from the Palestine Gazette (פלסטין גאזט), part of the Name Changes - Pre-State (שינוי שמות לפני קום המדינה) database, issue 1580, page 545, IGRA number 15544. The original records are from Avotaynu (אבותינו), This record was added to this search engine on 13 January 2016.

Gary Pokrassa