Board Thread:Questions and Answers/@comment-24191375-20150705192552/@comment-4509370-20150808235751

To give an answer, yes you can.

You can even try without needing to worry about losing it by exporting PTC to the SD card, deleting it off the System Memory and checking the eShop.

In general, it seems Nintendo's software policy is that if you have downloaded it once, you can redownload it anytime, even if it gets removed.

Though that's just for software, you can't redownload demos if they're gone, and most games have a similar warning with DLC.