WhatsApp is currently testing out new features on the Android Beta App which will allow users to revoke or edit messages you have already sent to other contacts. This feature isn’t available for regular users cannot access just yet.
These new features (edit sent message and revoke/recall message) have shown up in beta versions of WhatsApp for Android application, however they are disabled by default. This means that you will have to turn it on manually on a rooted phone. @WABetaInfo has shared images showing the upcoming feature on Android suggesting that WhatsApp for Android versions 2.17.25 and 2.17.26 will include the new edit and revoke features.
Apart from edit option, WhatsApp for Android users will also get a revoke option, as mentioned above, this just means that if you revoke a message, it will remove it even though it had already been sent.
The upcoming WhatsApp feature to edit or revoke sent message will work by long pressing a sent message. In order for the revoke and edit sent message feature to actually work, we assume that the recipient hasn’t yet seen the message from the sender. At the moment, WhatsApp allows users to delete messages on the device level and the deleted messages remain visible to the recipient.