Q. If one is sitting in a regular chair that does not have armrests, how can then reclining be done at the Seder?
A. Horav Shlomo Millers Shlit’a opinion is that, if one can’t recline on a neighboring chair, he may sit a bit sideways in his chair. so the back will be at an angle and he will be able to lean on his left side on it.
The Rov also permits to lean with his left hand on the table. (See similar ruling in Kovetz Halochos 21: 7)
Rabbi A. Bartfeld as revised by Horav Dovid Pam, Horav Aharon Miller and Horav Chanoch Ehrentreu Shlit’a