LIST<SBAA__ApprovalCondition__c> x = [select id, sbaa__testedfield__c,sbaa__approvalrule__r.CreatedDate from sbaa__approvalcondition__c
where sbaa__approvalrule__r.CreatedDate < 2020-04-02T00:00:00Z and sbaa__testedfield__c = 'HF2_Is_Created_Before_HF2_Live__c'];

for(SBAA__ApprovalCondition__c y : x){
    y.sbaa__testedfield__c = 'HF2_Old_Approval_Process__c';
}

upsert x;