Sometimes, the best thing to do is to simply get out of the way. An example of that approach...
"Dear Mr. White,
"In October of 2014, I wrote to you to tell you about our wonderful four legged friend Maggie, whom we adopted from the Peninsula SPCA in July of 1999. I don't know if you remember - you must get thousands of letters like mine - but I sent some pictures and you posted one along with my letter, on your blog.
"I had always intended to bring her by to meet you so I could show her off at the ripe old age of 16½. I thought it was pretty incredible that she was living so long and aging so well, and I knew we were very lucky. Well, I didn't bring her by, but our luck has continued and I'm writing today to tell you that she is still here: 18 years, 2 months, and 6 days later.
"She still has some good days yet we know we are about to lose her. It breaks our hearts, but that sadness will wane and we'll remember the joy and love she's brought to our lives. (Having just written this, Maggie and my husband, Jim, just came in from a nearly mile walk.)
"What you and your staff do every day is so important. You bring together people like me and furry friends like Maggie and we save each other. I can't imagine waking up every day without Maggie. It truly hurts to think about it, but eventually our hearts will heal and we will turn to you for another wonderful friend.
"As in 2014, I am ever so grateful to the Peninsula SPCA and all of you that save critters every day. Letting go is the hardest part of loving, and we have loved her unconditionally, as she has loved us. When the time comes, we will be back...
"Gratefully yours, Anne Sallot"