If you're using SendBoard to send/receive emails in Trello, you may occasionally receive two different emails concerning the same topic, resulting in two different Trello cards. It can be frustrating and messy to try and correspond separately on the two cards.
Here are a few simple steps you can take to merge two Trello cards so that you can continue correspondence on a single email thread. It'll only take you a minute.
Connect the cards
Trello provides a neat way for two cards to link to each other. By connecting two related Trello cards, you'll ensure information from both cards is easy to find. This won't affect what email messages your contacts will see, but at least you'll have a clear link between the cards in Trello.
To link two cards, open one of the cards and click on Attachment > Trello. You can search here for the other card, or copy the URL for the other card to add it as an attachment.
Once the attachment is added, you can click 'connect cards' to make the link work both ways.
Decide on a master card
You'll need to decide which of the two cards to use as the 'master card'. We'll call the other card the 'duplicate card'. The 'master' might be the earlier of the two emails you received. It might also be the email with the most relevant information on the topic. You'll need to decide which makes the most sense for you, but don't stress too much about it. As you'll find out below, your contacts will be able to see all of the messages from both threads anyway.
In some cases you might have different contacts on the two cards you are wanting to merge. To ensure that all participants are included in the thread moving forward, you'll want to copy contacts from the 'duplicate card' to the 'master card'. You'll do this when you send a reply email. Simply copy and paste the necessary email addresses from the 'duplicate' to the 'master'. You'll only have to do this once - from then on, the new contacts will be included in all further correspondence.
Because you are continuing the conversation from the master Trello card only, you'll want to ensure that important messages from the duplicate card are copied across. To do this, you can add the 'shareable link' from the duplicate card into your next reply. This will allow anyone on the email thread to easily access the full conversation from the duplicate email.
To get the shareable link, open the duplicate card, click the 'SendBoard' button and choose 'Get Shareable Link'. If you copy and paste this link into your reply, contacts can link through to that email thread to view any messages and attachments.
You can add a short message to your reply to explain that the emails have been merged.
Archive the duplicate card
Now that you've merged contacts and messages into the master card, you can go ahead and archive the duplicate card. If you feel it is necessary, you might also want to send out a message from the duplicate card, notifying contacts that the conversation has moved to a different thread and asking them not to reply further.