Clarify how absent members are handled in the Scala Improvement Process (#2802)

Author: julienrf

_sips/process-specification.md

@@ -199,12 +199,12 @@ the Implementation Stage. There are three possible outcomes:
   Committee.
 
 In order to be accepted for implementation and advance to the next stage, a SIP
-must gather strictly more than 50% of "Advance" votes among the members present
-(this means that an abstention is equivalent to "Do not advance" for this 
-purpose, biasing the process in favor of the status quo). The PR for the SIP is
-then also Merged at this point.
+must gather strictly more than 50% of "Advance" votes among the whole Committee. This means that an abstention is equivalent to "Do not advance" for this purpose, biasing the process in favor of the status quo. Furthermore, if more than half of the Committee members are absent at the meeting, the vote is cancelled.
 
-If there was no strict majority in favor of "Advance", a second vote between 
+For instance, if the Committee is made of 11 members, at least 6 members have to vote "Advance" for the SIP to move to the next stage.
+
+If there was a strict majority in favor of "Advance", the PR for the SIP is Merged at this point.
+Otherwise, a second vote between 
 Reject and Keep will be used. A proposal needs more than 50% "Reject" votes to
 be rejected in that case. Otherwise, it is kept.
 
@@ -288,6 +288,8 @@ have the following purposes:
 - Make any exception to the process that they judge necessary to unblock a 
   situation.
 
+If a Committee Member cannot attend a meeting, they are welcome to share their feedback about the proposals listed in the agenda of the meeting with the Chairperson, who will relate it during the meeting. A Committee Member cannot give their voting power to someone else. If a Committee Member misses more than 2 meetings within a year, they lose their seat.
+
 ### Responsibilities of the Committee Members
 
 - Review the proposals they are assigned to: