If you are considering setting up a fundraising event in memory of someone, you can do so easily by setting up a JustGiving page, Givetap page, a Facebook page, or on your desired donations platform. You may want to attach your activity to a particular 'in memory' event, such as a reception, or simply request donations in memory of your loved one to this page.  There are all sorts of ways to serve the memory of a loved one by serving charity.
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