It depends on the context of your amendment.
If the committee has already made a decision on the item in question and has moved on to something else, for example, when we are in a meeting and there are witnesses, 48 hours' notice must be given, because it does not relate to the matter before the committee at that time. However, if the debate is in progress and you have an amendment to move, you can move it immediately, without notice, because it deals with the business before the committee.
The same applies to motions before the committee. At your first meeting, you adopted routine motions that specify that if the item is related to the subject matter before the committee, such as business before the committee, the notice period is not required. However, if it relates to something else, notice must be given.