Ideally, one should make a completely new bed; but, often one doesn’t have the space to do that, or one or two roses have died in a bed, or one standard rose has died in a line, and one needs to replace in the same spot to keep the design looking good.
Dig out the old plant, make a good sized hole (at least 80 cm. x 80 cm. square and deep); discard the old soil – DO NOT USE ANY OF THIS “OLD” SOIL FOR THE NEW PLANT.
Fit a large cardboard box into the hole, and fill this with fresh soil, either from elsewhere in the garden, or buy some topsoil to fill it up. Add plenty of good compost, a little old manure, plus bone-meal or superphosphate. Then plant your new plant.
New roses do not thrive where roses have been grown before – so, if you must use the same position, you MUST do the above, or your new plants will never do well.