Question: Do I need to perform a token swap?
Answer: No. The rebranding from BCHA to eCash (XEC) was not a token swap. There were no changes to the blockchain. The rebrand simply changed how things are displayed to users in wallets and exchanges.
Question: What happenned to the BCHA token?
Answer: Nothing changed on the blockchain. Under the hood, "eCash" (XEC) is the same thing as "BCHA". The way it is displayed to users simply changed. So nothing happened to BCHA token, it just changed name to eCash/XEC, and the default base unit changed so that 1,000,000 XEC = 1 BCHA.
Question: What will happen if I send BCHA to an eCash wallet ?
Answer: If you send 1 BCHA to an eCash wallet, you will be credited 1,000,000 XEC. The conversion happens in the wallet, there is no change in the transaction format on the blockchain. Similarly, sending 1,000,000 XEC to a BCHA wallet will credit 1 BCHA on the receiving end.
Question: Is there a separate chain?
Answer: No, there is no separate chain. It is the same blockchain as before the rebrand. Just the way it is displayed to users changed.
Question: To change between address formats, can I simply edit the address by hand to change the prefix from "bitcoincash" to "ecash"?
Answer: You should use an address converter if you need to convert between address formats. The body of the address contains a checksum which covers the prefix, so simply cutting and pasting the prefix by itself will cause a mismatch.
Question: As a BCHA holder, what do I need to do for this rebranding?
Answer: BCHA holders didn't need to do anything. Even if you did nothing, the rebrand took place automatically. When you upgrade to a new wallet, the display changes automatically to show your holdings as eCash instead of BCHA. If you didn't upgrade your wallets, everything will continue to work as it did before. It is recommended to upgrade, as almost all wallets and exchanges now use eCash/XEC, so it is less confusing if you upgrade to a wallet that displays as eCash/XEC.