How do I allow a initial submitter of an approval process which is not a Salesforce admin to ReAssign the approval request to a reviewer after it has been submitted for approval.

I know Admins can do it since they can see and option to Reassign the request but how do I give the same permission to a user which is a submitter?

Trying to query lead object and retrieve list<leads> with more than 50,000 records 

SELECT Id, Name, Field1, Field2 FROM lead where Status = 'Eligible' ...........

Without using group by clause

I want to get all unique values of Store__c, so that I can use it to querry my store object later (I can't use group by here). My query looks like 

List<lead> listLead = [ SELECT  Store__c FROM Lead WHERE status = 'Eligible'];
Set<lead> random2 = new Set<lead>();
random2.addAll(listLead);
System.debug(random2);

The problem here is I am getting result for random2 as follows. I only want a set which has Store__c and not Id and RecordTypeId for lead

Lead: {Store__c=a0O1F000000R39cUAC, Id=00Q1F000002I6FFUA0, RecordTypeId=0121F000000B25UQAS}, 
Lead:{Store__c=a0O1F000000R4xqUAC, Id=00Q1F000002IBziUAG, RecordTypeId=0121F000000B25UQAS}}

Also, my next question is : how do I use this Set to query the Store__c object to get all unique Regions__c. (How do I iterate the list of stores in soql query) e.g select region__c from Store__c where id=  set of retrieved Store ids in previous query . Also, how efficient would it be?

Thanks

Trying to query lead object and retrieve list<leads> with more than 50,000 records 

SELECT Id, Name, Field1, Field2 FROM lead where Status = 'Eligible' ...........

Without using group by clause

I want to get all unique values of Store__c, so that I can use it to querry my store object later (I can't use group by here). My query looks like 

List<lead> listLead = [ SELECT  Store__c FROM Lead WHERE status = 'Eligible'];
Set<lead> random2 = new Set<lead>();
random2.addAll(listLead);
System.debug(random2);

The problem here is I am getting result for random2 as follows. I only want a set which has Store__c and not Id and RecordTypeId for lead

Lead: {Store__c=a0O1F000000R39cUAC, Id=00Q1F000002I6FFUA0, RecordTypeId=0121F000000B25UQAS}, 
Lead:{Store__c=a0O1F000000R4xqUAC, Id=00Q1F000002IBziUAG, RecordTypeId=0121F000000B25UQAS}}

Also, my next question is : how do I use this Set to query the Store__c object to get all unique Regions__c. (How do I iterate the list of stores in soql query) e.g select region__c from Store__c where id=  set of retrieved Store ids in previous query . Also, how efficient would it be?

Thanks