Tickers are sometimes reused. For example, since 2018,Ping An Healthcare has used the ticker 1833that hadpreviously been used by IntimeRetail whichhad delisted and given up the ticker. If I want to merge two financial datasets, which identifier should I use Ticker or FIGI?

to Return Delisting Detail Company Intime Retail Group Co Ltd Announced Date Effective Date 05/05/2017 05/22/2017 Exchange old Ticker MIC Code Reason Hong Kong Stock Exchange 1833 HK XHKG Acquired/Merged Action Id 145011914