How to say goodbye without saying goodbye in person before leaving and then texting?

If you have decided to leave and have no chance to say goodbye in person, then texting is an appropriate way. The following is a possible goodbye SMS template:

"[name of the other party],

I am writing this short note to tell you that I am leaving here. Although we didn't have a chance to say goodbye in person, I hope you can understand my decision.

[You can add some thanks or other words you want to express here]

I will miss the time we spent together. I hope to see you again if there is an opportunity in the future.

Please take care and wish you all the best.

[Your name] "

Please modify this template according to your specific situation to suit your specific situation.