Can I do intermittent fasting without losing weight?
Absolutely! Intermittent fasting covers a very wide range of eating patterns from daily time restricted feeding up to fasting for a few days each week. If you do not want to lose weight but still want to get some of the health benefits, try a shorter fasting window. You need to have at least a 12 hour fasting time, but the most popular seems to be 16:8, which involves fasting for 16 hours and typically skipping either breakfast or dinner.
If you are following one of the programs like 5:2 where they recommend fasting for 2 days each week, follow their guidelines for 500–600 calories for the low days instead of strict water-only fasting.
If you specifically don't want to lose weight, make sure that you are getting enough calories to meet your total daily energy requirement each day, or with an alternate day "fasting" aim for getting enough calories on average for the week.