This article will provide information on changing / re-labeling email tokens.
Image/data in this KBA is from SAP internal systems, sample data, or demo systems. Any resemblance to real data is purely coincidental.
SAP SuccessFactors Recruiting Management
As for how the system is designed to work right now, it is not possible to change tokens field keys.
SF, Success Factors, RCM, Field Key, Token re-labeling , KBA , LOD-SF-RCM , Recruiting Management , How To